chore: import upstream snapshot with attribution

books/PRML/PRML-master-Python/test/nn/math/multiply.py

@@ -0,0 +1,25 @@
+import unittest
+import numpy as np
+from prml import nn
+
+
+class TestMultiply(unittest.TestCase):
+
+    def test_multiply(self):
+        x = nn.Parameter(2)
+        y = x * 5
+        self.assertEqual(y.value, 10)
+        y.backward()
+        self.assertEqual(x.grad, 5)
+
+        x = np.random.rand(5, 4)
+        y = np.random.rand(4)
+        yp = nn.Parameter(y)
+        z = x * yp
+        self.assertTrue((z.value == x * y).all())
+        z.backward(np.ones((5, 4)))
+        self.assertTrue((yp.grad == x.sum(axis=0)).all())
+
+
+if __name__ == '__main__':
+    unittest.main()