feat(dnn): warpperspective support multi src input

GitOrigin-RevId: 8a4789852e

dnn/include/megdnn/oprs/imgproc.h

@@ -16,10 +16,18 @@ protected:
             const TensorLayout& src, const TensorLayout& mat, const TensorLayout& dst) {
         check_layout_fwd(src, mat, {}, dst);
     }
+    void check_layout_fwd(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& dst) {
+        check_layout_fwd(srcs, mat, {}, dst);
+    }
 
     void check_layout_fwd(
             const TensorLayout& src, const TensorLayout& mat,
             const TensorLayout& mat_idx, const TensorLayout& dst);
+    void check_layout_fwd(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& mat_idx, const TensorLayout& dst);
     std::string param_msg() const;
     int get_real_coord(int p, int len);
 };
@@ -49,6 +57,12 @@ public:
         exec(src, mat, {}, dst, workspace);
     }
 
+    void exec(
+            _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+            _megdnn_tensor_out dst, _megdnn_workspace workspace) {
+        exec(srcs, mat, {}, dst, workspace);
+    }
+
     /**
      * \p src should have batch size m, and \p mat and \p mat_idx should
      * both have batch size n. Each item in \p mat_idx must be in the range
@@ -62,15 +76,30 @@ public:
             _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
             _megdnn_tensor_out dst, _megdnn_workspace workspace) = 0;
 
+    virtual void exec(
+            _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+            _megdnn_tensor_in mat_idx, _megdnn_tensor_out dst,
+            _megdnn_workspace workspace) = 0;
+
     size_t get_workspace_in_bytes(
             const TensorLayout& src, const TensorLayout& mat, const TensorLayout& dst) {
         return get_workspace_in_bytes(src, mat, {}, dst);
     }
 
+    size_t get_workspace_in_bytes(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& dst) {
+        return get_workspace_in_bytes(srcs, mat, {}, dst);
+    }
+
     virtual size_t get_workspace_in_bytes(
             const TensorLayout& src, const TensorLayout& mat,
             const TensorLayout& mat_idx, const TensorLayout& dst) = 0;
 
+    virtual size_t get_workspace_in_bytes(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& mat_idx, const TensorLayout& dst) = 0;
+
 protected:
     void check_exec(
             const TensorLayout& src, const TensorLayout& mat,
@@ -81,6 +110,10 @@ protected:
             const TensorLayout& src, const TensorLayout& mat,
             const TensorLayout& mat_idx, const TensorLayout& dst,
             size_t workspace_in_bytes);
+    void check_exec_allow_nhwc_mat_idx(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& mat_idx, const TensorLayout& dst,
+            size_t workspace_in_bytes);
 };
 using WarpPerspective = WarpPerspectiveForward;
 

dnn/src/common/warp_common.cpp

@@ -22,4 +22,11 @@ bool warp::is_dnn_available(
     return imode == param::WarpAffine::InterpolationMode::LINEAR;
 }
 
+bool warp::is_dnn_available(
+        const TensorLayoutArray& /*src*/, const TensorLayout& /*mat*/,
+        const TensorLayout& /*dst*/, param::WarpAffine::InterpolationMode imode,
+        param::WarpAffine::Format /*format*/) {
+    return imode == param::WarpAffine::InterpolationMode::LINEAR;
+}
+
 // vim: syntax=cpp.doxygen

dnn/src/common/warp_common.h

@@ -90,6 +90,10 @@ bool is_dnn_available(
         const TensorLayout&, const TensorLayout&, const TensorLayout&,
         param::WarpAffine::InterpolationMode imode, param::WarpAffine::Format format);
 
+bool is_dnn_available(
+        const TensorLayoutArray&, const TensorLayout&, const TensorLayout&,
+        param::WarpAffine::InterpolationMode imode, param::WarpAffine::Format format);
+
 using namespace megcv;
 using IMode = InterpolationMode;
 using BMode = BorderMode;

dnn/src/common/warp_perspective.cpp

@@ -3,7 +3,97 @@
 #include "src/common/utils.h"
 
 namespace megdnn {
+void WarpPerspectiveBase::check_layout_fwd(
+        const TensorLayoutArray& srcs, const TensorLayout& mat,
+        const TensorLayout& mat_idx, const TensorLayout& dst) {
+    megdnn_assert(srcs.size() > 0);
+    auto s = srcs.front();
+    for (auto&& src : srcs) {
+        megdnn_assert_contiguous(src);
+        megdnn_assert(src.dtype == s.dtype);
+        megdnn_assert(src.ndim == s.ndim);
+        megdnn_assert(src.shape[0] == 1);
+        for (size_t i = 0; i < s.ndim; i++) {
+            megdnn_assert(src.shape[i] == s.shape[i]);
+        }
+        megdnn_assert(src.format == s.format);
+    }
+    megdnn_assert_contiguous(mat);
+    megdnn_assert_contiguous(dst);
+    auto errmsg = [&]() {
+        std::string msg = "{";
+        for (auto&& src : srcs) {
+            msg.append(megdnn_layout_msg(src) + ", ");
+        }
+        return msg + "} " + megdnn_layout_msg(mat) + ", " + megdnn_layout_msg(mat_idx) +
+               ", " + megdnn_layout_msg(dst) + ", " + param_msg();
+    };
+    MEGDNN_MARK_USED_VAR(errmsg);
+    megdnn_assert(
+            param().format == param::WarpPerspective::Format::NHWC ||
+            param().format == param::WarpPerspective::Format::NCHW);
+    megdnn_assert(s.ndim == 4_z, "%s", errmsg().c_str());
+    megdnn_assert(dst.ndim == 4_z, "%s", errmsg().c_str());
+    megdnn_assert(mat.ndim == 3_z, "%s", errmsg().c_str());
+    megdnn_assert(dst.shape[0] == mat.shape[0], "%s", errmsg().c_str());
+    if (mat_idx.ndim) {
+        megdnn_assert(
+                mat_idx.dtype == dtype::Int32() && mat_idx.ndim == 1, "%s",
+                errmsg().c_str());
+        megdnn_assert(mat.shape[0] == mat_idx.shape[0], "%s", errmsg().c_str());
+        megdnn_assert_contiguous(mat_idx);
+    } else {
+        megdnn_assert(s.shape[0] * srcs.size() == dst.shape[0], "%s", errmsg().c_str());
+    }
+    megdnn_assert(mat.shape[1] == 3_z, "%s", errmsg().c_str());
+    megdnn_assert(mat.shape[2] == 3_z, "%s", errmsg().c_str());
 
+    if (s.format == dst.format && dst.dtype == s.dtype) {
+        if (param().format == param::WarpPerspective::Format::NCHW) {
+            megdnn_assert(
+                    s.dtype.enumv() == DTypeEnum::Float32 ||
+                            DNN_FLOAT16_SELECT(
+                                    (s.dtype.enumv() == DTypeEnum::Float16 ||
+                                     s.dtype.enumv() == DTypeEnum::BFloat16),
+                                    false),
+                    "WarpPerspective multi src NCHW input dtype should be "
+                    "Float32" DNN_FLOAT16_SELECT("/Float16/BFloat16", "") ".");
+            megdnn_assert(
+                    (s.dtype.category() == DTypeCategory::FLOAT &&
+                     (s.dtype == mat.dtype || mat.dtype.enumv() == DTypeEnum::Float32)),
+                    "The input to WarpPerspective multi src is in NCHW format, in this "
+                    "case, if the input dtype is floating point, the "
+                    "transformation matrix should have same dtype as the "
+                    "input, otherwise, it should be in Float32, %s given.",
+                    mat.dtype.name());
+
+            megdnn_assert(s.shape[1] == dst.shape[1], "%s", errmsg().c_str());
+
+            megdnn_assert(
+                    param().imode == param::WarpPerspective::InterpolationMode::LINEAR);
+            megdnn_assert(
+                    param().bmode != param::WarpPerspective::BorderMode::TRANSPARENT);
+            megdnn_assert(
+                    param().bmode != param::WarpPerspective::BorderMode::ISOLATED);
+        } else {
+            megdnn_assert(param().format == param::WarpPerspective::Format::NHWC);
+            megdnn_assert(
+                    s.dtype.enumv() == DTypeEnum::Float32 ||
+                            DNN_FLOAT16_SELECT(
+                                    (s.dtype.enumv() == DTypeEnum::Float16 ||
+                                     s.dtype.enumv() == DTypeEnum::BFloat16),
+                                    false),
+                    "WarpPerspective multi src NHWC input dtype should be "
+                    "Float32" DNN_FLOAT16_SELECT("/Float16/BFloat16", "") ".");
+            megdnn_assert(s.shape[3] == dst.shape[3], "%s", errmsg().c_str());
+        }
+    } else {
+        megdnn_assert(
+                0,
+                "WarpPerspective multi src only support format NHWC/NCHW, dtype "
+                "Float32" DNN_FLOAT16_SELECT("/Float16/BFloat16", "") ".");
+    }
+}
 void WarpPerspectiveBase::check_layout_fwd(
         const TensorLayout& src, const TensorLayout& mat, const TensorLayout& mat_idx,
         const TensorLayout& dst) {
@@ -295,6 +385,19 @@ void WarpPerspectiveForward::check_exec_allow_nhwc_mat_idx(
     }
 }
 
+void WarpPerspectiveForward::check_exec_allow_nhwc_mat_idx(
+        const TensorLayoutArray& srcs, const TensorLayout& mat,
+        const TensorLayout& mat_idx, const TensorLayout& dst,
+        size_t workspace_in_bytes) {
+    check_layout_fwd(srcs, mat, mat_idx, dst);
+    auto required_workspace_in_bytes = get_workspace_in_bytes(srcs, mat, mat_idx, dst);
+    megdnn_assert(workspace_in_bytes >= required_workspace_in_bytes);
+    if (param().format != Param::Format::NHWC &&
+        param().format != Param::Format::NCHW) {
+        megdnn_assert(!mat_idx.ndim, "mat_idx not supported for current format");
+    }
+}
+
 void WarpPerspectiveBackwardData::check_exec(
         const TensorLayout& mat, const TensorLayout& mat_idx, const TensorLayout& diff,
         const TensorLayout& grad, size_t workspace_in_bytes) {

dnn/src/cuda/warp_perspective/common.h

@@ -17,6 +17,13 @@ void forward_proxy(
         ctype bval, BorderMode bmode, megcore::AsyncErrorInfo* error_info,
         void* error_tracker, cudaStream_t stream);
 
+template <typename ctype>
+void forward_proxy_multi_src(
+        bool is_nhwc, const ctype** srcs, const float* mat, const int* mat_idx,
+        ctype* dst, int N_SRC, int N_MAT, int C, int IH, int IW, int OH, int OW,
+        ctype bval, BorderMode bmode, megcore::AsyncErrorInfo* error_info,
+        void* error_tracker, cudaStream_t stream);
+
 template <typename ctype, int pack_c>
 void forward_proxy_nhwc_bit4(
         const ctype* src, const float* mat, const int* mat_idx, ctype* dst, int N_SRC,

dnn/src/cuda/warp_perspective/forward.cpp

@@ -143,6 +143,34 @@ WorkspaceBundle WarpPerspectiveForwardImpl::get_workspace_bundle(
     return {ptr, std::move(sizes)};
 }
 
+WorkspaceBundle WarpPerspectiveForwardImpl::get_workspace_bundle(
+        void* ptr, const TensorLayoutArray& srcs, const TensorLayout& mat,
+        const TensorLayout& mat_idx, const TensorLayout& dst) const {
+    MEGDNN_MARK_USED_VAR(mat_idx);
+    SmallVector<size_t> sizes;
+    TensorLayoutArray fsrcs = srcs;
+    TensorLayout fmat = mat;
+    TensorLayout fdst = dst;
+    auto get_workspace = [&sizes](TensorLayout& layout) {
+        if (layout.dtype == dtype::BFloat16()) {
+            layout.dtype = dtype::Float32();
+            sizes.push_back(layout.span().dist_byte());
+        }
+    };
+    for (auto&& fsrc : fsrcs) {
+        get_workspace(fsrc);
+    }
+    get_workspace(fmat);
+    get_workspace(fdst);
+    sizes.push_back(sizeof(dt_float32*) * srcs.size());
+    if (param().format == param::WarpPerspective::Format::NHWC) {
+        //! use double for the workspace dtype as float may cause
+        //! accuracy problems
+        sizes.push_back(mat.total_nr_elems() * sizeof(double));
+    }
+    return {ptr, std::move(sizes)};
+}
+
 void WarpPerspectiveForwardImpl::exec(
         _megdnn_tensor_in ssrc, _megdnn_tensor_in smat, _megdnn_tensor_in smat_idx,
         _megdnn_tensor_out sdst, _megdnn_workspace sworkspace) {
@@ -453,6 +481,124 @@ void WarpPerspectiveForwardImpl::exec(
     }
 }
 
+void WarpPerspectiveForwardImpl::exec(
+        _megdnn_in const TensorNDArray& ssrcs, _megdnn_tensor_in smat,
+        _megdnn_tensor_in smat_idx, _megdnn_tensor_out sdst,
+        _megdnn_workspace sworkspace) {
+    TensorLayoutArray ssrcs_layout;
+    for (auto&& s : ssrcs) {
+        ssrcs_layout.push_back(s.layout);
+    }
+    check_exec_allow_nhwc_mat_idx(
+            ssrcs_layout, smat.layout, smat_idx.layout, sdst.layout, sworkspace.size);
+
+    TensorNDArray srcs = ssrcs;
+    TensorND mat = smat;
+    TensorND mat_idx = smat_idx;
+    TensorND dst = sdst;
+    Param::Format inner_format = param().format;
+    auto bundle = get_workspace_bundle(
+            sworkspace.raw_ptr, ssrcs_layout, smat.layout, smat_idx.layout,
+            sdst.layout);
+    auto ctypecvt = CompTypeCvter<dtype::BFloat16, dtype::Float32>(
+            concrete_handle(this->handle()), &bundle);
+    if (ssrcs.front().layout.dtype.enumv() == DTypeTrait<dtype::BFloat16>::enumv) {
+        for (size_t i = 0; i < ssrcs.size(); i++) {
+            ctypecvt.src_to_comp_type(ssrcs[i], srcs[i]);
+        }
+        ctypecvt.src_to_comp_type(smat, mat).src_to_comp_type(sdst, dst);
+    }
+
+    {
+        auto stream = cuda_stream(this->handle());
+        bool is_nhwc = inner_format == param::WarpPerspective::Format::NHWC;
+        TensorND src = srcs.front();
+        megdnn_assert(warp::is_dnn_available(
+                ssrcs_layout, mat.layout, dst.layout, param().imode, inner_format));
+        size_t C, IH, IW, OH, OW;
+        if (is_nhwc) {
+            C = src.layout.shape[3];
+            IH = src.layout.shape[1];
+            IW = src.layout.shape[2];
+            OH = dst.layout.shape[1];
+            OW = dst.layout.shape[2];
+        } else {
+            megdnn_assert(
+                    inner_format == param::WarpPerspective::Format::NCHW,
+                    "invalid warp_perspective format");
+            C = src.layout.shape[1];
+            IH = src.layout.shape[2];
+            IW = src.layout.shape[3];
+            OH = dst.layout.shape[2];
+            OW = dst.layout.shape[3];
+        }
+        megdnn_assert(
+                param().imode == Param::InterpolationMode::LINEAR,
+                "unsupported interpolation mode form NCHW format");
+        auto bval = param().border_val;
+        auto bmode = warp_perspective::get_bmode(param().bmode);
+        if (src.layout.dtype == dst.layout.dtype) {
+            if (src.layout.dtype == dtype::Float32{}) {
+                SmallVector<size_t> workspace_sizes{sizeof(dt_float32*) * srcs.size()};
+                WorkspaceBundle workspace_cpu(nullptr, workspace_sizes);
+                auto total_workspace_size = workspace_cpu.total_size_in_bytes();
+                void* workspace_cpu_raw = malloc(total_workspace_size);
+                workspace_cpu = WorkspaceBundle(workspace_cpu_raw, workspace_sizes);
+                auto srcs_cpu = static_cast<const dt_float32**>(workspace_cpu.get(0));
+                size_t i =
+                        is_nhwc ? bundle.nr_workspace() - 2 : bundle.nr_workspace() - 1;
+                auto srcs_gpu = static_cast<const dt_float32**>(bundle.get(i));
+                for (size_t i = 0; i < srcs.size(); ++i) {
+                    srcs_cpu[i] = srcs[i].ptr<dt_float32>();
+                }
+                cuda_check(cudaMemcpyAsync(
+                        bundle.get(i), workspace_cpu.get(0), workspace_cpu.get_size(0),
+                        cudaMemcpyHostToDevice, stream));
+                cuda_check(cudaStreamAddCallback(
+                        stream, callback_free, static_cast<void*>(workspace_cpu_raw),
+                        0));
+                warp_perspective::forward_proxy_multi_src(
+                        is_nhwc, srcs_gpu, mat.ptr<dt_float32>(),
+                        mat_idx.raw_ptr() ? mat_idx.ptr<int>() : nullptr,
+                        dst.ptr<dt_float32>(), srcs.size(), mat.layout[0], C, IH, IW,
+                        OH, OW, bval, bmode, async_error_info(handle()),
+                        m_error_tracker, stream);
+            } else if (DNN_FLOAT16_SELECT(
+                               src.layout.dtype == dtype::Float16(), false)) {
+#ifndef MEGDNN_DISABLE_FLOAT16
+                SmallVector<size_t> workspace_sizes{sizeof(dt_float16*) * srcs.size()};
+                WorkspaceBundle workspace_cpu(nullptr, workspace_sizes);
+                auto total_workspace_size = workspace_cpu.total_size_in_bytes();
+                void* workspace_cpu_raw = malloc(total_workspace_size);
+                workspace_cpu = WorkspaceBundle(workspace_cpu_raw, workspace_sizes);
+                auto srcs_cpu = static_cast<const dt_float16**>(workspace_cpu.get(0));
+                auto srcs_gpu = static_cast<const dt_float16**>(bundle.get(0));
+                for (size_t i = 0; i < srcs.size(); ++i) {
+                    srcs_cpu[i] = srcs[i].ptr<dt_float16>();
+                }
+                cuda_check(cudaMemcpyAsync(
+                        bundle.get(0), workspace_cpu.get(0), workspace_cpu.get_size(0),
+                        cudaMemcpyHostToDevice, stream));
+                cuda_check(cudaStreamAddCallback(
+                        stream, callback_free, static_cast<void*>(workspace_cpu_raw),
+                        0));
+                warp_perspective::forward_proxy_multi_src(
+                        is_nhwc, srcs_gpu, mat.ptr<dt_float32>(),
+                        mat_idx.raw_ptr() ? mat_idx.ptr<int>() : nullptr,
+                        dst.ptr<dt_float16>(), srcs.size(), mat.layout[0], C, IH, IW,
+                        OH, OW, static_cast<dt_float16>(bval), bmode,
+                        async_error_info(handle()), m_error_tracker, stream);
+#endif
+            }
+        } else {
+            megdnn_throw(ssprintf("unsupported dtype: %s", src.layout.dtype.name()));
+        }
+    }
+    if (ssrcs.front().layout.dtype.enumv() == DTypeTrait<dtype::BFloat16>::enumv) {
+        ctypecvt.comp_to_dst_type(dst, sdst);
+    }
+}
+
 }  // namespace cuda
 }  // namespace megdnn
 

dnn/src/cuda/warp_perspective/forward.cu

@@ -47,11 +47,16 @@ struct CtypeHelper<dt_quint4> {
 template <typename ctype>
 struct DirectSrcVisitor {
     const void* ptr;
+    const void** ptrs;
 
     __device__ __forceinline__ const ctype* get(int batch, int im_size) {
         return (ctype*)((char*)ptr + static_cast<int64_t>(batch) * static_cast<int64_t>(im_size) * CtypeHelper<ctype>::bit_width / 8);
     }
 
+    __device__ __forceinline__ const ctype* get(int batch) {
+        return (ctype*)(ptrs[batch]);
+    }
+
     void move_batch(size_t batch, size_t im_size) {
         ptr = (char*)ptr + batch * im_size * CtypeHelper<ctype>::bit_width / 8;
     }
@@ -60,6 +65,7 @@ struct DirectSrcVisitor {
 template <typename ctype>
 struct IndexedSrcVisitor {
     const void* ptr;
+    const void** ptrs;
     const int* idx;
     int N_SRC;
 
@@ -79,11 +85,60 @@ struct IndexedSrcVisitor {
         return (ctype*)((char*)ptr + static_cast<int64_t>(batch) * static_cast<int64_t>(im_size) * CtypeHelper<ctype>::bit_width / 8);
     }
 
+    __device__ __forceinline__ const ctype* get(int batch) {
+        int orig_batch = batch;
+        batch = idx[batch];
+        if (batch < 0 || batch >= N_SRC) {
+            set_async_error_info(
+                    error_info, error_tracker,
+                    "mat_idx out of bound: mat_idx[%d]=%d src_batch=%d", orig_batch,
+                    batch, N_SRC);
+            batch = 0;
+        }
+        return (ctype*)(ptrs[batch]);
+    }
+
     void move_batch(size_t batch, size_t) { idx += batch; }
 };
 
 template <
         typename ctype, typename Getter, typename SrcVisitor, typename OutputConverter>
+__global__ void kern_general_multi_src(
+        SrcVisitor srcs, const float* __restrict mat, ctype* __restrict dst, int C,
+        int IH, int IW, int OH, int OW) {
+    Getter getter;
+    OutputConverter output_converter;
+    int ow = blockIdx.x * blockDim.x + threadIdx.x;
+    int oh = blockIdx.y * blockDim.y + threadIdx.y;
+    const ctype* __restrict sptr = srcs.get(blockIdx.z);
+    dst += blockIdx.z * C * OH * OW;
+    mat += blockIdx.z * 3 * 3;
+    if (ow < OW && oh < OH) {
+        float denominator = mat[6] * ow + mat[7] * oh + mat[8];
+        float iw = (mat[0] * ow + mat[1] * oh + mat[2]) / denominator;
+        float ih = (mat[3] * ow + mat[4] * oh + mat[5]) / denominator;
+        int iw0 = getter(floor(iw) + 0, IW);
+        int iw1 = getter(floor(iw) + 1, IW);
+        int ih0 = getter(floor(ih) + 0, IH);
+        int ih1 = getter(floor(ih) + 1, IH);
+        float palpha = ih - floor(ih);
+        float pbeta = iw - floor(iw);
+        float nalpha = 1.0f - palpha;
+        float nbeta = 1.0f - pbeta;
+        for (int c = 0; c < C; ++c) {
+            dst[oh * OW + ow] = output_converter(
+                    sptr[ih0 * IW + iw0] * nalpha * nbeta +
+                    sptr[ih0 * IW + iw1] * nalpha * pbeta +
+                    sptr[ih1 * IW + iw0] * palpha * nbeta +
+                    sptr[ih1 * IW + iw1] * palpha * pbeta);
+            sptr += IH * IW;
+            dst += OH * OW;
+        }
+    }
+}
+
+template <
+        typename ctype, typename Getter, typename SrcVisitor, typename OutputConverter>
 __global__ void kern_general(
         SrcVisitor src, const float* __restrict mat, ctype* __restrict dst, int C,
         int IH, int IW, int OH, int OW) {
@@ -262,6 +317,47 @@ __global__ void kern_general_nchw64(
 }
 
 template <typename ctype, typename SrcVisitor, typename OutputConverter>
+__global__ void kern_const_border_multi_src(
+        SrcVisitor srcs, const float* __restrict mat, ctype* __restrict dst, int C,
+        int IH, int IW, int OH, int OW, ctype bval) {
+    OutputConverter output_converter;
+    int ow = blockIdx.x * blockDim.x + threadIdx.x;
+    int oh = blockIdx.y * blockDim.y + threadIdx.y;
+    const ctype* __restrict sptr = srcs.get(blockIdx.z);
+    dst += blockIdx.z * C * OH * OW;
+    mat += blockIdx.z * 3 * 3;
+    if (ow < OW && oh < OH) {
+        float denominator = mat[6] * ow + mat[7] * oh + mat[8];
+        float iw = (mat[0] * ow + mat[1] * oh + mat[2]) / denominator;
+        float ih = (mat[3] * ow + mat[4] * oh + mat[5]) / denominator;
+        int iw0 = floor(iw) + 0;
+        int iw1 = floor(iw) + 1;
+        int ih0 = floor(ih) + 0;
+        int ih1 = floor(ih) + 1;
+        bool okw0 = (iw0 >= 0 && iw0 < IW);
+        bool okw1 = (iw1 >= 0 && iw1 < IW);
+        bool okh0 = (ih0 >= 0 && ih0 < IH);
+        bool okh1 = (ih1 >= 0 && ih1 < IH);
+        float palpha = ih - floor(ih);
+        float pbeta = iw - floor(iw);
+        float nalpha = 1.0f - palpha;
+        float nbeta = 1.0f - pbeta;
+        for (int c = 0; c < C; ++c) {
+            ctype v00 = (okh0 && okw0 ? sptr[ih0 * IW + iw0] : bval);
+            ctype v01 = (okh0 && okw1 ? sptr[ih0 * IW + iw1] : bval);
+            ctype v10 = (okh1 && okw0 ? sptr[ih1 * IW + iw0] : bval);
+            ctype v11 = (okh1 && okw1 ? sptr[ih1 * IW + iw1] : bval);
+            ctype val = output_converter(
+                    v00 * nalpha * nbeta + v01 * nalpha * pbeta + v10 * palpha * nbeta +
+                    v11 * palpha * pbeta);
+            dst[oh * OW + ow] = val;
+            sptr += IH * IW;
+            dst += OH * OW;
+        }
+    }
+}
+
+template <typename ctype, typename SrcVisitor, typename OutputConverter>
 __global__ void kern_const_border(
         SrcVisitor src, const float* __restrict mat, ctype* __restrict dst, int C,
         int IH, int IW, int OH, int OW, ctype bval) {
@@ -556,6 +652,51 @@ struct KernCoreNHWC<ctype, OutputConverter, 16> {
 template <
         typename ctype, typename Getter, typename SrcVisitor, typename OutputConverter,
         int pack_c>
+__global__ void kern_general_nhwc_multi_src(
+        SrcVisitor srcs, const float* __restrict mat, ctype* __restrict dst, int C,
+        int IH, int IW, int OH, int OW) {
+    Getter getter;
+    OutputConverter output_converter;
+    constexpr int bit_width = CtypeHelper<ctype>::bit_width;
+    int ow = blockIdx.x * blockDim.x + threadIdx.x;
+    int oh = blockIdx.y * blockDim.y + threadIdx.y;
+    const ctype* __restrict sptr = srcs.get(blockIdx.z);
+    dst = (ctype*)((char*)dst + blockIdx.z * C * OH * OW * bit_width / 8);
+    mat += blockIdx.z * 3 * 3;
+    if (ow < OW && oh < OH) {
+        float denominator = mat[6] * ow + mat[7] * oh + mat[8];
+        float iw = (mat[0] * ow + mat[1] * oh + mat[2]) / denominator;
+        float ih = (mat[3] * ow + mat[4] * oh + mat[5]) / denominator;
+        int iw0 = getter(floor(iw) + 0, IW);
+        int iw1 = getter(floor(iw) + 1, IW);
+        int ih0 = getter(floor(ih) + 0, IH);
+        int ih1 = getter(floor(ih) + 1, IH);
+        float palpha = ih - floor(ih);
+        float pbeta = iw - floor(iw);
+        float nalpha = 1.0f - palpha;
+        float nbeta = 1.0f - pbeta;
+        float w00 = nalpha * nbeta;
+        float w01 = nalpha * pbeta;
+        float w10 = palpha * nbeta;
+        float w11 = palpha * pbeta;
+        const char* src_ptr0 = (char*)sptr + (ih0 * IW + iw0) * C * bit_width / 8;
+        const char* src_ptr1 = (char*)sptr + (ih0 * IW + iw1) * C * bit_width / 8;
+        const char* src_ptr2 = (char*)sptr + (ih1 * IW + iw0) * C * bit_width / 8;
+        const char* src_ptr3 = (char*)sptr + (ih1 * IW + iw1) * C * bit_width / 8;
+        char* dst_ptr = (char*)dst + (oh * OW + ow) * C * bit_width / 8;
+
+        for (int c = 0; c < C; c += pack_c) {
+            KernCoreNHWC<ctype, OutputConverter, pack_c>::func(
+                    dst_ptr, src_ptr0, src_ptr1, src_ptr2, src_ptr3, c * bit_width / 8,
+                    w00, w01, w10, w11, output_converter, true, true, true, true,
+                    (ctype)0);
+        }
+    }
+}
+
+template <
+        typename ctype, typename Getter, typename SrcVisitor, typename OutputConverter,
+        int pack_c>
 __global__ void kern_general_nhwc(
         SrcVisitor src, const float* __restrict mat, ctype* __restrict dst, int C,
         int IH, int IW, int OH, int OW) {
@@ -601,6 +742,58 @@ __global__ void kern_general_nhwc(
 template <
         typename ctype, typename Getter, typename SrcVisitor, typename OutputConverter,
         int pack_c>
+__global__ void kern_general_nhwc_const_multi_src(
+        SrcVisitor srcs, const float* __restrict mat, ctype* __restrict dst, int C,
+        int IH, int IW, int OH, int OW, ctype bval) {
+    Getter getter;
+    OutputConverter output_converter;
+    constexpr int bit_width = CtypeHelper<ctype>::bit_width;
+    int ow = blockIdx.x * blockDim.x + threadIdx.x;
+    int oh = blockIdx.y * blockDim.y + threadIdx.y;
+    const ctype* __restrict sptr = srcs.get(blockIdx.z);
+    dst = (ctype*)((char*)dst + blockIdx.z * C * OH * OW * bit_width / 8);
+    mat += blockIdx.z * 3 * 3;
+    if (ow < OW && oh < OH) {
+        float denominator = mat[6] * ow + mat[7] * oh + mat[8];
+        float iw = (mat[0] * ow + mat[1] * oh + mat[2]) / denominator;
+        float ih = (mat[3] * ow + mat[4] * oh + mat[5]) / denominator;
+        int iw0 = getter(floor(iw) + 0, IW);
+        int iw1 = getter(floor(iw) + 1, IW);
+        int ih0 = getter(floor(ih) + 0, IH);
+        int ih1 = getter(floor(ih) + 1, IH);
+        float palpha = ih - floor(ih);
+        float pbeta = iw - floor(iw);
+        float nalpha = 1.0f - palpha;
+        float nbeta = 1.0f - pbeta;
+        float w00 = nalpha * nbeta;
+        float w01 = nalpha * pbeta;
+        float w10 = palpha * nbeta;
+        float w11 = palpha * pbeta;
+        const char* src_ptr0 = (char*)sptr + (ih0 * IW + iw0) * C * bit_width / 8;
+        const char* src_ptr1 = (char*)sptr + (ih0 * IW + iw1) * C * bit_width / 8;
+        const char* src_ptr2 = (char*)sptr + (ih1 * IW + iw0) * C * bit_width / 8;
+        const char* src_ptr3 = (char*)sptr + (ih1 * IW + iw1) * C * bit_width / 8;
+        char* dst_ptr = (char*)dst + (oh * OW + ow) * C * bit_width / 8;
+        bool okw0 = (iw0 >= 0 && iw0 < IW);
+        bool okw1 = (iw1 >= 0 && iw1 < IW);
+        bool okh0 = (ih0 >= 0 && ih0 < IH);
+        bool okh1 = (ih1 >= 0 && ih1 < IH);
+        bool src0_ok = okh0 && okw0;
+        bool src1_ok = okh0 && okw1;
+        bool src2_ok = okh1 && okw0;
+        bool src3_ok = okh1 && okw1;
+        for (int c = 0; c < C; c += pack_c) {
+            KernCoreNHWC<ctype, OutputConverter, pack_c>::func(
+                    dst_ptr, src_ptr0, src_ptr1, src_ptr2, src_ptr3, c * bit_width / 8,
+                    w00, w01, w10, w11, output_converter, src0_ok, src1_ok, src2_ok,
+                    src3_ok, bval);
+        }
+    }
+}
+
+template <
+        typename ctype, typename Getter, typename SrcVisitor, typename OutputConverter,
+        int pack_c>
 __global__ void kern_general_nhwc_const(
         SrcVisitor src, const float* __restrict mat, ctype* __restrict dst, int C,
         int IH, int IW, int OH, int OW, ctype bval) {
@@ -651,6 +844,73 @@ __global__ void kern_general_nhwc_const(
 }
 
 template <typename ctype, typename SrcVisitor>
+void dispatch_with_visitor_multi_src(
+        bool is_nhwc, SrcVisitor srcs, const float* mat, ctype* dst, int N, int C,
+        int IH, int IW, int OH, int OW, ctype bval, BorderMode bmode,
+        cudaStream_t stream) {
+    constexpr int pack_c = 1;
+    const int BY = 16, BX = 32;
+#define DISPATCH(Getter)                                                           \
+    do {                                                                           \
+        if (is_nhwc) {                                                             \
+            kern_general_nhwc_multi_src<                                           \
+                    ctype, Getter, SrcVisitor, rounding::RoundingConverter<ctype>, \
+                    pack_c><<<blocks, threads, 0, stream>>>(                       \
+                    srcs, mat, dst, C, IH, IW, OH, OW);                            \
+        } else {                                                                   \
+            kern_general_multi_src<                                                \
+                    ctype, Getter, SrcVisitor, rounding::RoundingConverter<ctype>> \
+                    <<<blocks, threads, 0, stream>>>(                              \
+                            srcs, mat, dst, C, IH, IW, OH, OW);                    \
+        }                                                                          \
+    } while (0)
+
+    const int max_batch_size = 65535;
+    while (N) {
+        size_t curr_batch_size = N < max_batch_size ? N : max_batch_size;
+        dim3 threads(BX, BY);
+        dim3 blocks((OW + BX - 1) / BX, (OH + BY - 1) / BY, curr_batch_size);
+
+        switch (bmode) {
+            case BORDER_REPLICATE:
+                DISPATCH(ReplicateGetter);
+                break;
+            case BORDER_REFLECT:
+                DISPATCH(ReflectGetter);
+                break;
+            case BORDER_REFLECT_101:
+                DISPATCH(Reflect101Getter);
+                break;
+            case BORDER_WRAP:
+                DISPATCH(WrapGetter);
+                break;
+#undef DISPATCH
+            case BORDER_CONSTANT:
+                if (is_nhwc) {
+                    kern_general_nhwc_const_multi_src<
+                            ctype, ConstGetter, SrcVisitor,
+                            rounding::RoundingConverter<ctype>, pack_c>
+                            <<<blocks, threads, 0, stream>>>(
+                                    srcs, mat, dst, C, IH, IW, OH, OW, bval);
+                } else {
+                    kern_const_border_multi_src<
+                            ctype, SrcVisitor, rounding::RoundingConverter<ctype>>
+                            <<<blocks, threads, 0, stream>>>(
+                                    srcs, mat, dst, C, IH, IW, OH, OW, bval);
+                }
+                break;
+            default:
+                break;
+        }
+
+        N -= curr_batch_size;
+        srcs.move_batch(curr_batch_size, C * IH * IW);
+        mat += curr_batch_size * 3 * 3;
+        dst += curr_batch_size * C * OH * OW;
+    }
+}
+
+template <typename ctype, typename SrcVisitor>
 void dispatch_with_visitor(
         bool is_nhwc, SrcVisitor src, const float* mat, ctype* dst, int N, int C,
         int IH, int IW, int OH, int OW, ctype bval, BorderMode bmode,
@@ -1534,6 +1794,33 @@ void dispatch_with_visitor_quint8_dimshuffle_typecvt_nchw(
 namespace megdnn {
 namespace cuda {
 namespace warp_perspective {
+template <typename ctype>
+void forward_proxy_multi_src(
+        bool is_nhwc, const ctype** srcs, const float* mat, const int* mat_idx,
+        ctype* dst, int N_SRC, int N_MAT, int C, int IH, int IW, int OH, int OW,
+        ctype bval, BorderMode bmode, megcore::AsyncErrorInfo* error_info,
+        void* error_tracker, cudaStream_t stream) {
+    if (mat_idx) {
+        IndexedSrcVisitor<ctype> visitor;
+        visitor.ptrs = reinterpret_cast<const void**>(srcs);
+        visitor.ptr = srcs;
+        visitor.idx = mat_idx;
+        visitor.N_SRC = N_SRC;
+        visitor.error_info = error_info;
+        visitor.error_tracker = error_tracker;
+        dispatch_with_visitor_multi_src(
+                is_nhwc, visitor, mat, dst, N_MAT, C, IH, IW, OH, OW, bval, bmode,
+                stream);
+    } else {
+        DirectSrcVisitor<ctype> visitor;
+        visitor.ptrs = reinterpret_cast<const void**>(srcs);
+        visitor.ptr = srcs;
+        dispatch_with_visitor_multi_src(
+                is_nhwc, visitor, mat, dst, N_MAT, C, IH, IW, OH, OW, bval, bmode,
+                stream);
+    }
+    after_kernel_launch();
+}
 
 template <typename ctype>
 void forward_proxy(
@@ -1643,6 +1930,17 @@ INST(dt_float16)
 INST(int8_t)
 #undef INST
 
+#define INST(ctype)                                                                    \
+    template void forward_proxy_multi_src(                                             \
+            bool, const ctype**, const float*, const int*, ctype*, int, int, int, int, \
+            int, int, int, ctype, BorderMode, megcore::AsyncErrorInfo*, void*,         \
+            cudaStream_t);
+INST(float)
+#ifndef MEGDNN_DISABLE_FLOAT16
+INST(dt_float16)
+#endif
+#undef INST
+
 #define INST(ctype)                                                                  \
     template void forward_proxy_nchw4(                                               \
             const ctype*, const float*, const int*, ctype*, int, int, int, int, int, \

dnn/src/cuda/warp_perspective/opr_impl.h

@@ -15,12 +15,22 @@ public:
     void exec(
             _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
             _megdnn_tensor_out dst, _megdnn_workspace workspace) override;
+    void exec(
+            _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+            _megdnn_tensor_in mat_idx, _megdnn_tensor_out dst,
+            _megdnn_workspace workspace) override;
     size_t get_workspace_in_bytes(
             const TensorLayout& src, const TensorLayout& mat,
             const TensorLayout& mat_idx, const TensorLayout& dst) override {
         return get_workspace_bundle(nullptr, src, mat, mat_idx, dst)
                 .total_size_in_bytes();
     }
+    size_t get_workspace_in_bytes(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& mat_idx, const TensorLayout& dst) override {
+        return get_workspace_bundle(nullptr, srcs, mat, mat_idx, dst)
+                .total_size_in_bytes();
+    }
 
     void set_error_tracker(void* tracker) override { m_error_tracker = tracker; }
 
@@ -28,6 +38,9 @@ private:
     WorkspaceBundle get_workspace_bundle(
             void* ptr, const TensorLayout& src, const TensorLayout& mat,
             const TensorLayout& mat_idx, const TensorLayout& dst) const;
+    WorkspaceBundle get_workspace_bundle(
+            void* ptr, const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& mat_idx, const TensorLayout& dst) const;
 };
 
 class WarpPerspectiveBackwardDataImpl final : public WarpPerspectiveBackwardData {

dnn/src/fallback/warp_perspective/opr_impl.cpp

@@ -51,6 +51,56 @@ size_t WarpPerspectiveImpl::get_workspace_in_bytes(
     }
 }
 
+size_t WarpPerspectiveImpl::get_workspace_in_bytes(
+        const TensorLayoutArray&, const TensorLayout&, const TensorLayout&,
+        const TensorLayout& dst) {
+    if (param().format == param::WarpPerspective::Format::NCHW) {
+        size_t OH = dst.shape[2], OW = dst.shape[3];
+        return get_bundle(OH, OW).total_size_in_bytes();
+    } else {
+        return 0;
+    }
+}
+
+void WarpPerspectiveImpl::exec(
+        _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+        _megdnn_tensor_in mat_idx, _megdnn_tensor_in dst, _megdnn_workspace workspace) {
+    TensorLayoutArray srcs_layout;
+    for (auto&& src : srcs) {
+        srcs_layout.push_back(src.layout);
+    }
+    check_exec_allow_nhwc_mat_idx(
+            srcs_layout, mat.layout, mat_idx.layout, dst.layout, workspace.size);
+    size_t nr_threads = static_cast<naive::HandleImpl*>(handle())
+                                ->megcore_dispatcher()
+                                ->nr_threads();
+    if (param().format == Format::NCHW && nr_threads == 1_z) {
+#define cb(dt, ct, mct)                                                                \
+    case DTypeTrait<dt>::enumv: {                                                      \
+        auto kparam = KernParam<ct, mct>::from_tensors(                                \
+                param().format, param().bmode, param().border_val, srcs, mat, mat_idx, \
+                dst, workspace);                                                       \
+        MIDOUT_BEGIN(megdnn_fallback_warpperspective, midout_iv(0), dt, ct, mct) {     \
+            MEGDNN_DISPATCH_CPU_KERN_OPR(kern_fallback_multi_src(kparam));             \
+            return;                                                                    \
+        }                                                                              \
+        MIDOUT_END();                                                                  \
+    }
+        switch (srcs.front().layout.dtype.enumv()) {
+            cb(dtype::Float32, float, float);
+            DNN_INC_FLOAT16(cb(dtype::Float16, dt_float16, float));
+            default:
+                megdnn_throw(ssprintf(
+                                     "Unsupported input DType in "
+                                     "WarpPerspective: %s",
+                                     srcs.front().layout.dtype.name())
+                                     .c_str());
+        }
+#undef cb
+    }
+    naive::WarpPerspectiveForwardImpl::exec(srcs, mat, mat_idx, dst, workspace);
+}
+
 void WarpPerspectiveImpl::exec(
         _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
         _megdnn_tensor_in dst, _megdnn_workspace workspace) {
@@ -96,6 +146,69 @@ void WarpPerspectiveImpl::exec(
 }
 
 template <typename ctype, typename mtype>
+void WarpPerspectiveImpl::kern_fallback_multi_src(
+        const KernParam<ctype, mtype>& kern_param) {
+    UNPACK_WARP_PERSPECTIVE_FWD_KERN_PARAM(kern_param);
+    // cause error if accidentally used
+    sptr = nullptr;
+    mptr = nullptr;
+    dptr = nullptr;
+    MEGDNN_MARK_USED_VAR(sptr);
+    MEGDNN_MARK_USED_VAR(mptr);
+    MEGDNN_MARK_USED_VAR(dptr);
+    MEGDNN_MARK_USED_VAR(border_val);
+
+    MEGDNN_MARK_USED_VAR(IH);
+    MEGDNN_MARK_USED_VAR(IW);
+    KernParam<ctype, mtype> sub_param = kern_param;
+    sub_param.n_src = 1;
+    sub_param.n_mat = 1;
+    sub_param.midx_ptr = RefPtr();
+    sub_param.src_ptr = RefPtr(kern_param.srcs_ptr.front().get_ptr());
+    sub_param.mat_ptr = RefPtr(kern_param.mat_ptr.get_ptr());
+    sub_param.dst_ptr = RefPtr(kern_param.dst_ptr.get_ptr());
+    sub_param.srcs_ptr = kern_param.srcs_ptr;
+
+    rep(n, N_MAT) {
+        if (midx_ptr) {
+            size_t idx = midx_ptr[n];
+            megdnn_assert(
+                    idx < N_SRC, "mat_idx out of bound: mat_idx[%zu]=%zu src_batch=%zu",
+                    n, idx, N_SRC);
+            sub_param.src_ptr.reset(
+                    static_cast<ctype*>(kern_param.srcs_ptr[idx].get_ptr()));
+        } else if (n) {
+            sub_param.src_ptr.reset(
+                    static_cast<ctype*>(kern_param.srcs_ptr[n].get_ptr()));
+        }
+        if (is_resize_optimizable(static_cast<mtype*>(sub_param.mat_ptr.get_ptr()))) {
+            if (bmode == BorderMode::CONSTANT) {
+                MIDOUT_BEGIN(
+                        megdnn_fallback_warpperspective, midout_iv(1), midout_iv(true),
+                        ctype, mtype) {
+                    kern_resize<true, ctype, mtype>(sub_param);
+                }
+                MIDOUT_END();
+            } else {
+                MIDOUT_BEGIN(
+                        megdnn_fallback_warpperspective, midout_iv(1), midout_iv(false),
+                        ctype, mtype) {
+                    kern_resize<false, ctype, mtype>(sub_param);
+                }
+                MIDOUT_END();
+            }
+        } else {
+            MIDOUT_BEGIN(megdnn_fallback_warpperspective, midout_iv(2), ctype, mtype) {
+                rep(oh, OH) kern_naive<ctype, mtype>(sub_param, oh);
+            }
+            MIDOUT_END();
+        }
+        sub_param.mat_ptr += 3 * 3 * sizeof(mtype);
+        sub_param.dst_ptr += C * OH * OW * sizeof(ctype);
+    }
+}
+
+template <typename ctype, typename mtype>
 void WarpPerspectiveImpl::kern_fallback(const KernParam<ctype, mtype>& kern_param) {
     UNPACK_WARP_PERSPECTIVE_FWD_KERN_PARAM(kern_param);
 

dnn/src/fallback/warp_perspective/opr_impl.h

@@ -9,14 +9,24 @@ protected:
     template <typename ctype, typename mtype>
     void kern_fallback(const KernParam<ctype, mtype>& kern_param);
 
+    template <typename ctype, typename mtype>
+    void kern_fallback_multi_src(const KernParam<ctype, mtype>& kern_param);
+
 public:
     using naive::WarpPerspectiveForwardImpl::WarpPerspectiveForwardImpl;
     size_t get_workspace_in_bytes(
             const TensorLayout& src, const TensorLayout& mat,
             const TensorLayout& mat_idx, const TensorLayout& dst) override;
+    size_t get_workspace_in_bytes(
+            const TensorLayoutArray& srcs, const TensorLayout& mat,
+            const TensorLayout& mat_idx, const TensorLayout& dst) override;
     void exec(
             _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
             _megdnn_tensor_out dst, _megdnn_workspace workspace) override;
+    void exec(
+            _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+            _megdnn_tensor_in mat_idx, _megdnn_tensor_out dst,
+            _megdnn_workspace workspace) override;
 
 private:
     template <typename ctype>

dnn/src/naive/warp_perspective/opr_impl.cpp

@@ -15,6 +15,119 @@ using namespace megdnn;
 using namespace naive;
 
 template <typename ctype, typename mtype>
+void WarpPerspectiveForwardImpl::kern_naive_multi_src(
+        const KernParam<ctype, mtype>& kern_param, size_t task_id) {
+    MEGDNN_MARK_USED_VAR(kern_param);
+    MIDOUT_BEGIN(megdnn_naive_warpperspective, ctype, mtype, midout_iv(0)) {
+        UNPACK_WARP_PERSPECTIVE_FWD_KERN_PARAM(kern_param);
+        MEGDNN_MARK_USED_VAR(N_MAT);
+        //! strides of C, H, W on src and dst
+        size_t sstrd[3], dstrd[3];
+        auto set_sstrd = [&](size_t s0, size_t s1, size_t s2) {
+            sstrd[0] = s0;
+            sstrd[1] = s1;
+            sstrd[2] = s2;
+        };
+        auto set_dstrd = [&](size_t s0, size_t s1, size_t s2) {
+            dstrd[0] = s0;
+            dstrd[1] = s1;
+            dstrd[2] = s2;
+        };
+        switch (kern_param.format) {
+            case Format::NCHW:
+                set_sstrd(IH * IW, IW, 1);
+                set_dstrd(OH * OW, OW, 1);
+                break;
+            case Format::NHWC:
+                set_sstrd(1, IW * C, C);
+                set_dstrd(1, OW * C, C);
+                break;
+            default:
+                megdnn_throw("bad format");
+        }
+
+        auto visit_src = [&sptr, sstrd](size_t c, int h, int w) -> float {
+            return sptr[sstrd[0] * c + sstrd[1] * h + sstrd[2] * w];
+        };
+        auto visit_src_bd = [&sptr, sstrd, border_val](
+                                    size_t c, int h, int w) -> float {
+            if (h != -1 && w != -1) {
+                return sptr[sstrd[0] * c + sstrd[1] * h + sstrd[2] * w];
+            } else
+                return border_val;
+        };
+        auto visit_dst = [&dptr, dstrd](size_t c, int h, int w) -> ctype& {
+            return dptr[dstrd[0] * c + dstrd[1] * h + dstrd[2] * w];
+        };
+
+        rounding::RoundingConverter<ctype> output_converter;
+        sptr = static_cast<const ctype*>(kern_param.srcs_ptr.front().get_ptr());
+        size_t n = task_id / OH;
+        size_t oh = task_id % OH;
+        mptr = mptr + n * 3 * 3;
+        dptr = dptr + n * C * OH * OW;
+        if (midx_ptr) {
+            size_t idx = midx_ptr[n];
+            megdnn_assert(
+                    idx < N_SRC, "mat_idx out of bound: mat_idx[%zu]=%zu src_batch=%zu",
+                    n, idx, N_SRC);
+            sptr = sptrs[idx];
+        } else if (n) {
+            sptr = sptrs[n];
+        }
+        rep(ow, OW) {
+            float numeratorw = mptr[0] * ow + mptr[1] * oh + mptr[2];
+            float numeratorh = mptr[3] * ow + mptr[4] * oh + mptr[5];
+            float denominator = mptr[6] * ow + mptr[7] * oh + mptr[8];
+            float alphaw = numeratorw / denominator;
+            float alphah = numeratorh / denominator;
+
+            int iw0 = get_real_coord(std::floor(alphaw) + 0, IW);
+            int iw1 = get_real_coord(std::floor(alphaw) + 1, IW);
+            int ih0 = get_real_coord(std::floor(alphah) + 0, IH);
+            int ih1 = get_real_coord(std::floor(alphah) + 1, IH);
+
+            alphaw -= floor(alphaw);
+            alphah -= floor(alphah);
+            if (bmode != BorderMode::CONSTANT) {
+                rep(c, C) {
+                    visit_dst(c, oh, ow) = output_converter(
+                            visit_src(c, ih0, iw0) * (1.0f - alphaw) * (1.0f - alphah) +
+                            visit_src(c, ih0, iw1) * alphaw * (1.0f - alphah) +
+                            visit_src(c, ih1, iw0) * (1.0f - alphaw) * alphah +
+                            visit_src(c, ih1, iw1) * alphaw * alphah);
+                }
+            } else {
+                rep(c, C) {
+                    auto val = visit_src_bd(c, ih0, iw0) * (1.0f - alphaw) *
+                                       (1.0f - alphah) +
+                               visit_src_bd(c, ih0, iw1) * alphaw * (1.0f - alphah) +
+                               visit_src_bd(c, ih1, iw0) * (1.0f - alphaw) * alphah +
+                               visit_src_bd(c, ih1, iw1) * alphaw * alphah;
+                    visit_dst(c, oh, ow) =
+                            output_converter(std::isfinite(val) ? val : border_val);
+                }
+            }
+        }
+    }
+    MIDOUT_END();
+}
+
+#define INST(ctype, mtype)                                                        \
+    template void WarpPerspectiveForwardImpl::kern_naive_multi_src<ctype, mtype>( \
+            const KernParam<ctype, mtype>&, size_t);
+
+INST(float, float);
+#if !MEGDNN_DISABLE_FLOAT16
+INST(dt_float16, float);
+INST(dt_float16, dt_float16);
+INST(dt_bfloat16, float);
+INST(dt_bfloat16, dt_bfloat16);
+#endif
+
+#undef INST
+
+template <typename ctype, typename mtype>
 void WarpPerspectiveForwardImpl::kern_naive(
         const KernParam<ctype, mtype>& kern_param, size_t task_id) {
     MEGDNN_MARK_USED_VAR(kern_param);
@@ -505,6 +618,71 @@ INST(uint8_t, float, float);
 #undef INST
 
 void WarpPerspectiveForwardImpl::exec(
+        _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+        _megdnn_tensor_in mat_idx, _megdnn_tensor_out dst,
+        _megdnn_workspace workspace) {
+    TensorLayoutArray srcs_layout;
+    for (auto&& src : srcs) {
+        srcs_layout.push_back(src.layout);
+    }
+    check_exec_allow_nhwc_mat_idx(
+            srcs_layout, mat.layout, mat_idx.layout, dst.layout, workspace.size);
+    size_t batch = dst.layout[0];
+
+#define KERN_NAIVE_MULTI_SRC(ct, mct)                                              \
+    auto kparam = KernParam<ct, mct>::from_tensors(                                \
+            param().format, param().bmode, param().border_val, srcs, mat, mat_idx, \
+            dst, workspace);                                                       \
+    auto run = [kparam, this](size_t index, size_t) {                              \
+        kern_naive_multi_src(kparam, index);                                       \
+    };                                                                             \
+    MEGDNN_DISPATCH_MULTI_THREAD_CPU_KERN_OPR(run, kparam.oh* batch);
+
+#define DISPATCH_ST_MULTI_SRC(dt, ct, mct, kern)                      \
+    if (srcs.front().layout.dtype.enumv() == DTypeTrait<dt>::enumv) { \
+        kern(ct, mct);                                                \
+        return;                                                       \
+    }
+
+#define DISPATCH_ST_MT_MULTI_SRC(dt, ct, kern)                               \
+    if (srcs.front().layout.dtype.enumv() == DTypeTrait<dt>::enumv) {        \
+        if (mat.layout.dtype.enumv() == DTypeTrait<dtype::Float32>::enumv) { \
+            kern(ct, float);                                                 \
+            return;                                                          \
+        } else {                                                             \
+            kern(ct, ct);                                                    \
+            return;                                                          \
+        }                                                                    \
+    }
+
+    megdnn_assert(warp::is_dnn_available(
+            srcs_layout, mat.layout, dst.layout, param().imode, param().format));
+    /*!
+     * We currently use floating point for all WarpPerspective
+     * computation, so even if the input ctype is one of the integer
+     * type, mtype should always be float32.
+     *
+     * \warning It's different with \c WarpAffine, with mtype be float16
+     * if input type is float16.
+     */
+
+    DISPATCH_ST_MULTI_SRC(dtype::Float32, float, float, KERN_NAIVE_MULTI_SRC);
+    DNN_INC_FLOAT16(
+            DISPATCH_ST_MT_MULTI_SRC(dtype::Float16, dt_float16, KERN_NAIVE_MULTI_SRC));
+    DNN_INC_FLOAT16(DISPATCH_ST_MT_MULTI_SRC(
+            dtype::BFloat16, dt_bfloat16, KERN_NAIVE_MULTI_SRC));
+    megdnn_throw(ssprintf(
+                         "Unsupported input DType in "
+                         "WarpPerspective: %s",
+                         srcs.front().layout.dtype.name())
+                         .c_str());
+
+#undef KERN_NAIVE_MULTI_SRC
+#undef DISPATCH_ST_MT_MULTI_SRC
+#undef DISPATCH_ST_MULTI_SRC
+}
+
+void WarpPerspectiveForwardImpl::exec(
         _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
         _megdnn_tensor_out dst, _megdnn_workspace workspace) {
     check_exec_allow_nhwc_mat_idx(

dnn/src/naive/warp_perspective/opr_impl.h

@@ -17,10 +17,72 @@ protected:
         DType src_dtype, dst_dtype;
         RefPtr src_ptr, mat_ptr, dst_ptr;
         RefPtr midx_ptr;  //!< can be null
+        SmallVector<RefPtr> srcs_ptr;
         Workspace workspace;
 
         static KernParam from_tensors(
                 Format format, BorderMode bmode, float border_val,
+                _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+                _megdnn_tensor_in mat_idx, _megdnn_tensor_out dst,
+                _megdnn_workspace workspace) {
+            auto src = srcs.front();
+            KernParam ret;
+            ret.format = format;
+            ret.bmode = bmode;
+            ret.border_val = border_val;
+            ret.n_src = srcs.size();
+            ret.src_dtype = src.layout.dtype;
+            ret.dst_dtype = dst.layout.dtype;
+
+            if (mat_idx.raw_ptr()) {
+                megdnn_assert(mat_idx.layout.ndim == 1);
+                ret.n_mat = mat_idx.layout.shape[0];
+                ret.midx_ptr = mat_idx.get_ref_ptr();
+            } else {
+                megdnn_assert(mat_idx.layout.ndim == 0);
+                ret.n_mat = ret.n_src;
+                ret.midx_ptr = nullptr;
+            }
+
+            if (format == Format::NCHW) {
+                ret.c = src.layout.shape[1];
+                ret.ih = src.layout.shape[2];
+                ret.iw = src.layout.shape[3];
+                ret.oh = dst.layout.shape[2];
+                ret.ow = dst.layout.shape[3];
+            } else {
+                megdnn_assert(format == Format::NHWC);
+                ret.c = src.layout.shape[3];
+                ret.ih = src.layout.shape[1];
+                ret.iw = src.layout.shape[2];
+                ret.oh = dst.layout.shape[1];
+                ret.ow = dst.layout.shape[2];
+            }
+
+            if ((src.layout.dtype.enumv() == DTypeEnum::Float32 ||
+                 DNN_FLOAT16_SELECT(
+                         (src.layout.dtype.enumv() == DTypeEnum::Float16 ||
+                          src.layout.dtype.enumv() == DTypeEnum::BFloat16),
+                         false)) &&
+                (src.layout.dtype == dst.layout.dtype)) {
+                for (auto&& s : srcs) {
+                    ret.srcs_ptr.push_back(s.get_ref_ptr());
+                }
+                ret.mat_ptr = mat.get_ref_ptr();
+                ret.dst_ptr = dst.get_ref_ptr();
+            } else {
+                for (size_t i = 0; i < srcs.size(); i++) {
+                    ret.srcs_ptr.push_back(nullptr);
+                }
+                ret.mat_ptr = nullptr;
+                ret.dst_ptr = nullptr;
+            }
+            ret.src_ptr = nullptr;
+            ret.workspace = workspace;
+            return ret;
+        }
+        static KernParam from_tensors(
+                Format format, BorderMode bmode, float border_val,
                 _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
                 _megdnn_tensor_out dst, _megdnn_workspace workspace) {
             KernParam ret;
@@ -124,16 +186,29 @@ protected:
     template <typename ctype, typename mtype>
     void kern_naive(const KernParam<ctype, mtype>& kern_param, size_t task_id);
 
+    template <typename ctype, typename mtype>
+    void kern_naive_multi_src(
+            const KernParam<ctype, mtype>& kern_param, size_t task_id);
+
 public:
     using WarpPerspectiveForward::WarpPerspectiveForward;
     void exec(
             _megdnn_tensor_in src, _megdnn_tensor_in mat, _megdnn_tensor_in mat_idx,
             _megdnn_tensor_out dst, _megdnn_workspace workspace) override;
+    void exec(
+            _megdnn_in const TensorNDArray& srcs, _megdnn_tensor_in mat,
+            _megdnn_tensor_in mat_idx, _megdnn_tensor_out dst,
+            _megdnn_workspace workspace) override;
     size_t get_workspace_in_bytes(
             const TensorLayout&, const TensorLayout&, const TensorLayout&,
             const TensorLayout&) override {
         return 0;
     }
+    size_t get_workspace_in_bytes(
+            const TensorLayoutArray&, const TensorLayout&, const TensorLayout&,
+            const TensorLayout&) override {
+        return 0;
+    }
 
 private:
     template <typename ctype, typename mtype>
@@ -253,6 +328,10 @@ private:
     auto mptr = static_cast<const mtype*>(p.mat_ptr.get_ptr());                      \
     auto dptr = static_cast<ctype*>(p.dst_ptr.get_ptr());                            \
     auto midx_ptr = static_cast<int*>(p.midx_ptr.get_ptr());                         \
+    SmallVector<const ctype*> sptrs;                                                 \
+    for (auto&& s_ptr : p.srcs_ptr) {                                                \
+        sptrs.push_back(static_cast<const ctype*>(s_ptr.get_ptr()));                 \
+    }                                                                                \
     auto bmode = p.bmode;                                                            \
     float border_val = p.border_val
 

dnn/test/common/warp_perspective.cpp

@@ -50,6 +50,54 @@ void WarpPerspectiveMatIdxProxy::exec(
             tensors[0], tensors[1], tensors[2], tensors[3], tensors[4], W.workspace());
 }
 
+void WarpPerspectiveMultiSrcProxy::deduce_layout(
+        WarpPerspectiveForward*, TensorLayoutArray&) {}
+
+void WarpPerspectiveMultiSrcProxy::exec(
+        WarpPerspectiveForward* opr, const TensorNDArray& tensors) {
+    if (!W.valid()) {
+        W = WorkspaceWrapper(opr->handle(), 0);
+    }
+    megdnn_assert(tensors.size() >= 3);
+    bool has_mat_idx = false;
+    TensorLayout mat_idx_layout;
+    TensorND mat_idx_tensor;
+
+    TensorLayoutArray layouts(tensors.size());
+    std::transform(
+            tensors.begin(), tensors.end(), layouts.begin(),
+            [](const TensorND& tensor) { return tensor.layout; });
+    auto srcs_layouts = layouts;
+    srcs_layouts.pop_back();  // dst
+    if (srcs_layouts.back().ndim == 1) {
+        has_mat_idx = true;
+        mat_idx_layout = srcs_layouts.back();
+        srcs_layouts.pop_back();  // mat_idx;
+    }
+    auto mat_layout = srcs_layouts.back();
+    srcs_layouts.pop_back();  // mat
+
+    if (has_mat_idx)
+        W.update(opr->get_workspace_in_bytes(
+                srcs_layouts, mat_layout, mat_idx_layout, layouts.back()));
+    else
+        W.update(opr->get_workspace_in_bytes(srcs_layouts, mat_layout, layouts.back()));
+    auto srcs_tensors = tensors;
+    srcs_tensors.pop_back();  // dst
+    if (has_mat_idx) {
+        mat_idx_tensor = srcs_tensors.back();
+        srcs_tensors.pop_back();  // mat_idx;
+    }
+    auto mat_tensor = srcs_tensors.back();
+    srcs_tensors.pop_back();  // mat
+    if (has_mat_idx)
+        opr->exec(
+                srcs_tensors, mat_tensor, mat_idx_tensor, tensors.back(),
+                W.workspace());
+    else
+        opr->exec(srcs_tensors, mat_tensor, tensors.back(), W.workspace());
+}
+
 std::vector<TestArg> warp_perspective::get_cv_args() {
     std::vector<TestArg> args;
 

dnn/test/common/warp_perspective.h

@@ -19,6 +19,12 @@ struct WarpPerspectiveMatIdxProxy {
     void exec(WarpPerspectiveBackwardMat* opr, const TensorNDArray& tensors);
 };
 
+struct WarpPerspectiveMultiSrcProxy {
+    WorkspaceWrapper W;
+    static void deduce_layout(WarpPerspectiveForward*, TensorLayoutArray&);
+    void exec(WarpPerspectiveForward* opr, const TensorNDArray& tensors);
+};
+
 class WarpPerspectiveMatRNG final : public IIDRNG {
 public:
     WarpPerspectiveMatRNG() : idx(0) {}

dnn/test/cuda/warp_perspective.cpp

@@ -887,6 +887,194 @@ TEST_F(CUDA, WARP_PERSPECTIVE_NCHW64_QUINT4) {
     }
 }
 
+TEST_F(CUDA, WARP_PERSPECTIVE_MULTI_SRC_NCHW) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NCHW;
+
+        auto run = [&param, &rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle_cuda());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, c, ih, iw}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{bs, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // dst
+            shapes.emplace_back(TensorShape{{bs, c, oh, ow}});
+            checker.set_dtype(bs + 1, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, dtype);
+            run(2, 100, 110, 10, 50, 50, dtype);
+            run(20, 10, 11, 123, 15, 16, dtype);
+            run(2200, 10, 11, 3, 11, 12, dtype);
+        }
+    }
+}
+
+TEST_F(CUDA, WARP_PERSPECTIVE_MULTI_SRC_NHWC) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NHWC;
+
+        auto run = [&param, &rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle_cuda());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, ih, iw, c}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{bs, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // dst
+            shapes.emplace_back(TensorShape{{bs, oh, ow, c}});
+            checker.set_dtype(bs + 1, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, dtype);
+            run(2, 100, 110, 10, 50, 50, dtype);
+            run(20, 10, 11, 123, 15, 16, dtype);
+            run(2200, 10, 11, 3, 11, 12, dtype);
+        }
+    }
+}
+
+TEST_F(CUDA, WARP_PERSPECTIVE_MULTI_SRC_WITH_IDX_NCHW) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+    UniformIntRNG idx_rng{0, 0};
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NCHW;
+
+        auto run = [&param, &rng, &idx_rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, size_t idx, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle_cuda());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, c, ih, iw}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{idx, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // mat_idx
+            shapes.emplace_back(TensorShape{{idx}});
+            checker.set_dtype(bs + 1, dtype::Int32());
+            idx_rng = UniformIntRNG{0, (int)bs - 1};
+            checker.set_rng(bs + 1, &idx_rng);
+            // dst
+            shapes.emplace_back(TensorShape{{idx, c, oh, ow}});
+            checker.set_dtype(bs + 2, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, 1, dtype);
+            run(2, 100, 110, 10, 50, 50, 1, dtype);
+            run(20, 10, 11, 123, 15, 16, 10, dtype);
+            run(2200, 10, 11, 3, 11, 12, 100, dtype);
+        }
+    }
+}
+
+TEST_F(CUDA, WARP_PERSPECTIVE_MULTI_SRC_WITH_IDX_NHWC) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+    UniformIntRNG idx_rng{0, 0};
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NHWC;
+
+        auto run = [&param, &rng, &idx_rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, size_t idx, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle_cuda());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, ih, iw, c}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{idx, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // mat_idx
+            shapes.emplace_back(TensorShape{{idx}});
+            checker.set_dtype(bs + 1, dtype::Int32());
+            idx_rng = UniformIntRNG{0, (int)bs - 1};
+            checker.set_rng(bs + 1, &idx_rng);
+            // dst
+            shapes.emplace_back(TensorShape{{idx, oh, ow, c}});
+            checker.set_dtype(bs + 2, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, 1, dtype);
+            run(2, 100, 110, 10, 50, 50, 1, dtype);
+            run(20, 10, 11, 123, 15, 16, 10, dtype);
+            run(2200, 10, 11, 3, 11, 12, 100, dtype);
+        }
+    }
+}
+
 #if MEGDNN_WITH_BENCHMARK
 
 TEST_F(CUDA, BENCHMARK_WARP_PERSPECTIVE_NCHW4) {

dnn/test/fallback/warp_perspective.cpp

@@ -172,6 +172,190 @@ TEST_F(FALLBACK, WARP_PERSPECTIFVE_NCHW_QUINT8) {
     warp_perspective::run_quint8_test(handle());
 }
 
+TEST_F(FALLBACK, WARP_PERSPECTIVE_MULTI_SRC_NCHW) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NCHW;
+
+        auto run = [&param, &rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, c, ih, iw}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{bs, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // dst
+            shapes.emplace_back(TensorShape{{bs, c, oh, ow}});
+            checker.set_dtype(bs + 1, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, dtype);
+            run(20, 10, 11, 123, 15, 16, dtype);
+            run(100, 10, 11, 3, 11, 12, dtype);
+        }
+    }
+}
+
+TEST_F(FALLBACK, WARP_PERSPECTIVE_MULTI_SRC_NHWC) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NHWC;
+
+        auto run = [&param, &rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, ih, iw, c}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{bs, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // dst
+            shapes.emplace_back(TensorShape{{bs, oh, ow, c}});
+            checker.set_dtype(bs + 1, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, dtype);
+            run(20, 10, 11, 123, 15, 16, dtype);
+            run(100, 10, 11, 3, 11, 12, dtype);
+        }
+    }
+}
+
+TEST_F(FALLBACK, WARP_PERSPECTIVE_MULTI_SRC_WITH_IDX_NCHW) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+    UniformIntRNG idx_rng{0, 0};
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NCHW;
+
+        auto run = [&param, &rng, &idx_rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, size_t idx, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, c, ih, iw}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{idx, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // mat_idx
+            shapes.emplace_back(TensorShape{{idx}});
+            checker.set_dtype(bs + 1, dtype::Int32());
+            idx_rng = UniformIntRNG{0, (int)bs - 1};
+            checker.set_rng(bs + 1, &idx_rng);
+            // dst
+            shapes.emplace_back(TensorShape{{idx, c, oh, ow}});
+            checker.set_dtype(bs + 2, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, 1, dtype);
+            run(20, 10, 11, 123, 15, 16, 10, dtype);
+            run(100, 10, 11, 3, 11, 12, 100, dtype);
+        }
+    }
+}
+
+TEST_F(FALLBACK, WARP_PERSPECTIVE_MULTI_SRC_WITH_IDX_NHWC) {
+    using Param = WarpPerspective::Param;
+    Param param;
+    WarpPerspectiveMatRNG rng;
+    UniformIntRNG idx_rng{0, 0};
+
+    for (auto bmode :
+         {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+          WarpPerspective::BorderMode::REPLICATE,
+          WarpPerspective::BorderMode::CONSTANT}) {
+        param.border_val = 0.3f;
+        param.bmode = bmode;
+        param.imode = Param::InterpolationMode::LINEAR;
+        param.format = Param::Format::NHWC;
+
+        auto run = [&param, &rng, &idx_rng, this](
+                           size_t bs, size_t ih, size_t iw, size_t c, size_t oh,
+                           size_t ow, size_t idx, DType dtype) {
+            Checker<WarpPerspectiveForward, WarpPerspectiveMultiSrcProxy> checker(
+                    handle());
+            checker.set_param(param);
+            TensorShapeArray shapes;
+            // src
+            for (size_t i = 0; i < bs; i++) {
+                shapes.emplace_back(TensorShape{{1, ih, iw, c}});
+                checker.set_dtype(i, dtype);
+            }
+            // mat
+            shapes.emplace_back(TensorShape{{idx, 3, 3}});
+            checker.set_rng(bs, &rng);
+            // mat_idx
+            shapes.emplace_back(TensorShape{{idx}});
+            checker.set_dtype(bs + 1, dtype::Int32());
+            idx_rng = UniformIntRNG{0, (int)bs - 1};
+            checker.set_rng(bs + 1, &idx_rng);
+            // dst
+            shapes.emplace_back(TensorShape{{idx, oh, ow, c}});
+            checker.set_dtype(bs + 2, dtype);
+            checker.execs(shapes);
+        };
+
+        for (auto dtype : std::vector<DType>{dtype::Float32(), dtype::Float16()}) {
+            run(1, 20, 18, 4, 6, 6, 1, dtype);
+            run(20, 10, 11, 123, 15, 16, 10, dtype);
+            run(100, 10, 11, 3, 11, 12, 100, dtype);
+        }
+    }
+}
+
 }  // namespace test
 }  // namespace megdnn
 

dnn/test/naive/warp_perspective.cpp

@@ -55,6 +55,282 @@ class NanMatRNG : public RNG {
 };
 }  // namespace
 
+TEST_F(NAIVE, WARP_PERSPECTIVE_MULTI_SRC) {
+    using Param = WarpPerspective::Param;
+
+    WarpPerspective::Param param;
+    auto extra_impl = [&param, this](const TensorNDArray& tensors) {
+        //! split src
+        TensorND src = tensors[0];  // n h w c
+        size_t n = src.layout[0];
+        TensorNDArray srcs;  // n 个 1 h w c
+        TensorLayoutArray srcs_layouts;
+        for (size_t i = 0; i < n; i++) {
+            TensorLayout ly;
+            ly = TensorLayout{
+                    {1, src.layout[1], src.layout[2], src.layout[3]}, src.layout.dtype};
+            srcs.emplace_back(malloc(ly.span().dist_byte()), ly);
+            srcs_layouts.emplace_back(ly);
+        }
+
+        auto split = handle()->create_operator<SplitForward>();
+        split->param().axis = 0;
+        auto split_ws_size = split->get_workspace_in_bytes(src.layout, srcs_layouts);
+        dt_byte* split_ws_ptr = static_cast<dt_byte*>(malloc(split_ws_size));
+        Workspace split_ws{split_ws_ptr, split_ws_size};
+        split->exec(src, srcs, split_ws);
+
+        auto warp_perspective = handle()->create_operator<WarpPerspective>();
+        warp_perspective->param() = param;
+        auto warp_ws_size = warp_perspective->get_workspace_in_bytes(
+                srcs_layouts, tensors[1].layout, tensors[2].layout);
+        dt_byte* warp_ws_ptr = static_cast<dt_byte*>(malloc(warp_ws_size));
+        Workspace warp_ws{warp_ws_ptr, warp_ws_size};
+        warp_perspective->exec(srcs, tensors[1], tensors[2], warp_ws);
+
+        free(split_ws_ptr);
+        free(warp_ws_ptr);
+        for (auto&& s : srcs) {
+            free(s.raw_ptr());
+        }
+    };
+
+    {
+        // Float32
+        Checker<WarpPerspectiveForward> checker(handle());
+        WarpPerspectiveMatRNG rng;
+        checker.set_rng(1, &rng);
+        checker.set_extra_opr_impl(extra_impl);
+        // NHWC
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NHWC;
+            checker.set_param(param);
+            checker.execs({{1, 2, 2, 4}, {1, 3, 3}, {1, 2, 2, 4}});
+            checker.execs({{2, 10, 10, 4}, {2, 3, 3}, {2, 10, 12, 4}});
+            checker.execs({{3, 25, 24, 8}, {3, 3, 3}, {3, 12, 10, 8}});
+            checker.execs({{4, 33, 22, 16}, {4, 3, 3}, {4, 9, 12, 16}});
+        }
+        // NCHW
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NCHW;
+            checker.set_param(param);
+            checker.execs({{1, 4, 2, 2}, {1, 3, 3}, {1, 4, 2, 2}});
+            checker.execs({{2, 4, 10, 10}, {2, 3, 3}, {2, 4, 10, 12}});
+            checker.execs({{3, 8, 25, 24}, {3, 3, 3}, {3, 8, 12, 10}});
+            checker.execs({{4, 16, 33, 22}, {4, 3, 3}, {4, 16, 9, 12}});
+        }
+    }
+
+    {
+        // Float16
+        Checker<WarpPerspectiveForward> checker(handle());
+        WarpPerspectiveMatRNG rng;
+        checker.set_rng(1, &rng);
+        checker.set_dtype(0, dtype::Float16());
+        checker.set_dtype(2, dtype::Float16());
+        checker.set_extra_opr_impl(extra_impl);
+        // NHWC
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NHWC;
+            checker.set_param(param);
+            checker.execs({{1, 2, 2, 4}, {1, 3, 3}, {1, 2, 2, 4}});
+            checker.execs({{2, 10, 10, 4}, {2, 3, 3}, {2, 10, 12, 4}});
+            checker.execs({{3, 25, 24, 8}, {3, 3, 3}, {3, 12, 10, 8}});
+            checker.execs({{4, 33, 22, 16}, {4, 3, 3}, {4, 9, 12, 16}});
+        }
+        // NCHW
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NCHW;
+            checker.set_param(param);
+            checker.execs({{1, 4, 2, 2}, {1, 3, 3}, {1, 4, 2, 2}});
+            checker.execs({{2, 4, 10, 10}, {2, 3, 3}, {2, 4, 10, 12}});
+            checker.execs({{3, 8, 25, 24}, {3, 3, 3}, {3, 8, 12, 10}});
+            checker.execs({{4, 16, 33, 22}, {4, 3, 3}, {4, 16, 9, 12}});
+        }
+    }
+}
+
+TEST_F(NAIVE, WARP_PERSPECTIVE_MULTI_SRC_WITH_IDX) {
+    using Param = WarpPerspective::Param;
+
+    WarpPerspective::Param param;
+    auto extra_impl = [&param, this](const TensorNDArray& tensors) {
+        //! split src
+        TensorND src = tensors[0];  // n h w c
+        size_t n = src.layout[0];
+        TensorNDArray srcs;  // n 个 1 h w c
+        TensorLayoutArray srcs_layouts;
+        for (size_t i = 0; i < n; i++) {
+            TensorLayout ly;
+            ly = TensorLayout{
+                    {1, src.layout[1], src.layout[2], src.layout[3]}, src.layout.dtype};
+            srcs.emplace_back(malloc(ly.span().dist_byte()), ly);
+            srcs_layouts.emplace_back(ly);
+        }
+
+        auto split = handle()->create_operator<SplitForward>();
+        split->param().axis = 0;
+        auto split_ws_size = split->get_workspace_in_bytes(src.layout, srcs_layouts);
+        dt_byte* split_ws_ptr = static_cast<dt_byte*>(malloc(split_ws_size));
+        Workspace split_ws{split_ws_ptr, split_ws_size};
+        split->exec(src, srcs, split_ws);
+
+        auto warp_perspective = handle()->create_operator<WarpPerspective>();
+        warp_perspective->param() = param;
+        auto warp_ws_size = warp_perspective->get_workspace_in_bytes(
+                srcs_layouts, tensors[1].layout, tensors[2].layout, tensors[3].layout);
+        dt_byte* warp_ws_ptr = static_cast<dt_byte*>(malloc(warp_ws_size));
+        Workspace warp_ws{warp_ws_ptr, warp_ws_size};
+        warp_perspective->exec(srcs, tensors[1], tensors[2], tensors[3], warp_ws);
+
+        free(split_ws_ptr);
+        free(warp_ws_ptr);
+        for (auto&& s : srcs) {
+            free(s.raw_ptr());
+        }
+    };
+
+    {
+        // Float32
+        Checker<WarpPerspectiveForward, WarpPerspectiveMatIdxProxy> checker(handle());
+        WarpPerspectiveMatRNG rng;
+        checker.set_rng(1, &rng);
+        checker.set_dtype(0, dtype::Float32());
+        checker.set_dtype(1, dtype::Float32());
+        checker.set_dtype(2, dtype::Int32());
+        checker.set_dtype(3, dtype::Float32());
+        checker.set_extra_opr_impl(extra_impl);
+        // NHWC
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NHWC;
+            checker.set_param(param);
+            UniformIntRNG idx_rng{0, 0};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{1, 2, 2, 4}, {1, 3, 3}, {1}, {1, 2, 2, 4}});
+            idx_rng = UniformIntRNG{0, 1};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{2, 10, 10, 4}, {1, 3, 3}, {1}, {1, 10, 12, 4}});
+            idx_rng = UniformIntRNG{0, 2};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{3, 25, 24, 8}, {2, 3, 3}, {2}, {2, 12, 10, 8}});
+            checker.execs({{4, 33, 22, 16}, {2, 3, 3}, {2}, {2, 9, 12, 16}});
+        }
+        // NCHW
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NCHW;
+            checker.set_param(param);
+            UniformIntRNG idx_rng{0, 0};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{1, 4, 2, 2}, {1, 3, 3}, {1}, {1, 4, 2, 2}});
+            idx_rng = UniformIntRNG{0, 1};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{2, 4, 10, 10}, {1, 3, 3}, {1}, {1, 4, 10, 12}});
+            idx_rng = UniformIntRNG{0, 2};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{3, 8, 25, 24}, {2, 3, 3}, {2}, {2, 8, 12, 10}});
+            checker.execs({{4, 16, 33, 22}, {2, 3, 3}, {2}, {2, 16, 9, 12}});
+        }
+    }
+
+    {
+        // Float16
+        Checker<WarpPerspectiveForward, WarpPerspectiveMatIdxProxy> checker(handle());
+        WarpPerspectiveMatRNG rng;
+        checker.set_rng(1, &rng);
+        checker.set_dtype(0, dtype::Float16());
+        checker.set_dtype(1, dtype::Float32());
+        checker.set_dtype(2, dtype::Int32());
+        checker.set_dtype(3, dtype::Float16());
+        checker.set_extra_opr_impl(extra_impl);
+        // NHWC
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NHWC;
+            checker.set_param(param);
+            UniformIntRNG idx_rng{0, 0};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{1, 2, 2, 4}, {1, 3, 3}, {1}, {1, 2, 2, 4}});
+            idx_rng = UniformIntRNG{0, 1};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{2, 10, 10, 4}, {1, 3, 3}, {1}, {1, 10, 12, 4}});
+            idx_rng = UniformIntRNG{0, 2};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{3, 25, 24, 8}, {2, 3, 3}, {2}, {2, 12, 10, 8}});
+            checker.execs({{4, 33, 22, 16}, {2, 3, 3}, {2}, {2, 9, 12, 16}});
+        }
+        // NCHW
+        for (auto bmode :
+             {WarpPerspective::BorderMode::WRAP, WarpPerspective::BorderMode::REFLECT,
+              WarpPerspective::BorderMode::REPLICATE,
+              WarpPerspective::BorderMode::CONSTANT}) {
+            param.border_val = 0.3f;
+            param.bmode = bmode;
+            param.imode = Param::InterpolationMode::LINEAR;
+
+            param.format = Param::Format::NCHW;
+            checker.set_param(param);
+            UniformIntRNG idx_rng{0, 0};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{1, 4, 2, 2}, {1, 3, 3}, {1}, {1, 4, 2, 2}});
+            idx_rng = UniformIntRNG{0, 1};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{2, 4, 10, 10}, {1, 3, 3}, {1}, {1, 4, 10, 12}});
+            idx_rng = UniformIntRNG{0, 2};
+            checker.set_rng(2, &idx_rng);
+            checker.execs({{3, 8, 25, 24}, {2, 3, 3}, {2}, {2, 8, 12, 10}});
+            checker.execs({{4, 16, 33, 22}, {2, 3, 3}, {2}, {2, 16, 9, 12}});
+        }
+    }
+}
+
 TEST_F(NAIVE, WARP_PERSPECTIVE_NCHW4) {
     using Param = WarpPerspective::Param;