fix(mgb/dnn): fix backward computation of tqt

GitOrigin-RevId: 850d11a5ce

dnn/src/cuda/tqt/kern.cuh

@@ -58,7 +58,7 @@ struct TQTBwdKernOp {
         ctype scaled = input[idx] / t;
         ctype rounded = round(scaled);
         rounded = fmaxf(fminf(rounded, qmax), qmin);
-        bool mask_clip = scaled < -0.5 + qmin && scaled > 0.5 + qmax;
+        bool mask_clip = (scaled < -0.5 + qmin) + (scaled > 0.5 + qmax);
         bool mask_quant = !mask_clip;
 
         grad_x[idx] = diff[idx] * mask_quant;

dnn/src/naive/tqt/opr_impl.cpp

@@ -53,7 +53,7 @@ void backward_impl(const ElemwiseOpParamN<5> src, float qmin, float qmax) {
         T rounded = round(scaled);
         rounded = rounded <= qmin ? qmin : rounded;
         rounded = rounded >= qmax ? qmax : rounded;
-        bool mask_clip = scaled < -0.5 + qmin && scaled > 0.5 + qmax;
+        bool mask_clip = (scaled < -0.5 + qmin) + (scaled > 0.5 + qmax);
         bool mask_quant = !mask_clip;
 
         *grad_x = *diff * mask_quant;

imperative/python/test/unit/quantization/test_fake_quant.py

@@ -69,8 +69,8 @@ def test_tqt():
     def cb(grad):
         g.append(grad)
 
-    x = np.random.normal(size=(1, 2, 3, 4))
-    s = np.random.rand(1) + 1
+    x = np.random.randint(-128, 128, size=(1, 2, 3, 4)).astype("float32")
+    s = np.random.rand(1) - 1
     g_y = np.ones(shape=(1, 2, 3, 4), dtype="float32")
 
     n = TQT_numpy(-127, 127)
@@ -85,9 +85,9 @@ def test_tqt():
     grad(y, g_y)
     g_x, g_s = g
 
-    np.testing.assert_allclose(y.numpy(), y_np, atol=1e-6)
-    np.testing.assert_allclose(g_x.numpy(), g_x_np, atol=1e-6)
-    np.testing.assert_allclose(g_s.numpy(), g_s_np, atol=1e-6)
+    np.testing.assert_allclose(y.numpy(), y_np, rtol=1e-5, atol=1e-5)
+    np.testing.assert_allclose(g_x.numpy(), g_x_np, rtol=1e-5, atol=1e-5)
+    np.testing.assert_allclose(g_s.numpy(), g_s_np, rtol=5e-5, atol=5e-5)