!882 fix bug of bprop of FloorMod

Merge pull request !882 from zhangbuxue/fix_bprop_for_floor_mod

mindspore/ops/_grad/grad_math_ops.py

@@ -255,13 +255,10 @@ def get_bprop_floordiv(self):
 @bprop_getters.register(P.FloorMod)
 def get_bprop_floormod(self):
     """Grad definition for `FloorMod` operation."""
-    div_op = P.FloorMod()
-    neg = P.Neg()
-    mul_op = P.Mul()
 
     def bprop(x, y, out, dout):
-        bc_x = div_op(dout, y)
-        bc_y = neg(mul_op(bc_x, out))
+        bc_x = dout
+        bc_y = -dout * (x // y)
         return binop_grad_common(x, y, bc_x, bc_y)
     return bprop
 
@@ -412,6 +409,7 @@ def get_bprop_reducesum(self):
 def get_bprop_cumsum(self):
     """Grad definition for `CumSum` operation."""
     cumsum = P.CumSum(exclusive=self.exclusive, reverse=not self.reverse)
+
     def bprop(x, axis, out, dout):
         return cumsum(dout, axis), zeros_like(axis)
     return bprop
@@ -787,6 +785,7 @@ def get_bprop_atan2(self):
     """Generate bprop for Atan2"""
 
     square = P.Square()
+
     def bprop(x, y, out, dout):
         tmp = dout / (square(x) + square(y))
         dx = tmp * y

tests/ut/python/ops/test_ops.py

@@ -351,9 +351,8 @@ test_case_math_ops = [
         'skip': ['backward']}),
     ('FloorMod', {
         'block': P.FloorMod(),
-        'desc_inputs': [Tensor(np.random.rand(4).astype(np.float16)),
-                        Tensor(np.random.rand(4).astype(np.float16))],
-        'skip': ['backward']}),
+        'desc_inputs': [[3, 4, 5], [2, 3, 4, 5]],
+        'desc_bprop': [[2, 3, 4, 5]]}),
     ('identity', {
         'block': ops.functional.identity,
         'desc_inputs': [[2, 2]],