diff --git a/requirements.txt b/requirements.txt
index 47a91a1..24d6efe 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,6 +5,7 @@ networkx>=2.2
 scikit-learn>=0.20.0
 tabulate>=0.8.2
 tqdm>=4.26.0
-cvxpy>=1.0.31 # for preimage.
+cvxpy>=1.0.31 # for preimage. Does not work for "pip install graphkit-learn".
+# -e https://files.pythonhosted.org/packages/11/d0/d900870dc2d02ea74961b90c353666c6528a33ea61a10aa59a0d5574ae59/cvxpy-1.0.31.tar.gz # for preimage.
 cvxopt>=1.2.5 # for preimage.
 mosek>=9.2.5; python_version >= '3.6' # for preimage.
diff --git a/requirements_pypi.txt b/requirements_pypi.txt
new file mode 100644
index 0000000..f4854fc
--- /dev/null
+++ b/requirements_pypi.txt
@@ -0,0 +1,11 @@
+numpy>=1.16.2
+scipy>=1.1.0
+matplotlib>=3.0.0
+networkx>=2.2
+scikit-learn>=0.20.0
+tabulate>=0.8.2
+tqdm>=4.26.0
+# cvxpy>=1.0.31 # for preimage. Does not work for "pip install graphkit-learn".
+# -e https://files.pythonhosted.org/packages/11/d0/d900870dc2d02ea74961b90c353666c6528a33ea61a10aa59a0d5574ae59/cvxpy-1.0.31.tar.gz # for preimage.
+cvxopt>=1.2.5 # for preimage.
+mosek>=9.2.5; python_version >= '3.6' # for preimage.
diff --git a/setup.py b/setup.py
index 932002c..a84679e 100644
--- a/setup.py
+++ b/setup.py
@@ -3,12 +3,12 @@ import setuptools
 with open("README.md", "r") as fh:
     long_description = fh.read()
 
-with open('requirements.txt') as fp:
+with open('requirements_pypi.txt') as fp:
     install_requires = fp.read()
 
 setuptools.setup(
     name="graphkit-learn",
-    version="0.2b1",
+    version="0.2b2",
     author="Linlin Jia",
     author_email="linlin.jia@insa-rouen.fr",
     description="A Python library for graph kernels, graph edit distances, and graph pre-images",