change '/' method from scale Op to elementwise_div Op (#33279)

* fix the bug of div operation result using scale method do not exactly equal the result of elementwise_div method

* remove __div__ , __rdiv__ methods which do not define in python3

* modify the note

* add test case

* add test case

Author: MingMingShangTian

python/paddle/fluid/dygraph/math_op_patch.py

@@ -46,9 +46,7 @@
     '__rsub__',
     '__mul__',
     '__rmul__',
-    '__div__',
     '__truediv__',
-    '__rdiv__',
     '__rtruediv__',
     '__matmul__',
 ]
@@ -168,9 +166,6 @@ def _scalar_rsub_(var, value):
     def _scalar_mul_(var, value):
         return _scalar_elementwise_op_(var, value, 0.0)
 
-    def _scalar_div_(var, value):
-        return _scalar_elementwise_op_(var, 1.0 / value, 0.0)
-
     # for binary operator such as elementwise, compare
     def _binary_creator_(method_name,
                          op_type,
@@ -201,7 +196,10 @@ def __impl__(self, other_var):
                 if op_type == 'elementwise_div' and self.dtype in _supported_int_dtype_:
                     self = astype(self, 'float32')
                 # here use `scale` replace `elementwise` to get better performance
-                # but only +, -, *, / can use this method
+                # but only +, -, * can use this method
+                # NOTE(chentianyu03): / can not use `scale` method，because the result of
+                # `scale` method (self*(1/other_var)) do not exactly equal with the result 
+                # of `elementwise_div` method.
                 if scalar_method is not None:
                     return scalar_method(self, other_var)
             else:
@@ -288,12 +286,8 @@ def __impl__(self, other_var):
         ## a*b == b*a. Do not need to reverse explicitly
         ('__rmul__',
          _binary_creator_('__rmul__', 'elementwise_mul', False, _scalar_mul_)),
-        ('__div__', _binary_creator_('__div__', 'elementwise_div', False,
-                                     _scalar_div_)),
         ('__truediv__', _binary_creator_('__truediv__', 'elementwise_div',
-                                         False, _scalar_div_)),
-        ('__rdiv__', _binary_creator_('__rdiv__', 'elementwise_div', True,
-                                      None)),
+                                         False, None)),
         ('__rtruediv__', _binary_creator_('rtruediv__', 'elementwise_div', True,
                                           None)),
         ('__pow__', _binary_creator_('__pow__', 'elementwise_pow', False,

python/paddle/fluid/layers/math_op_patch.py

@@ -39,9 +39,7 @@
     "__rsub__": "A -= B",
     "__mul__": "A * B",
     "__rmul__": "A *= B",
-    "__div__": "A / B",
     "__truediv__": "A / B",
-    "__rdiv__": "A /= B",
     "__rtruediv__": "A /= B",
     "__pow__": "A ** B",
     "__rpow__": "A **= B",
@@ -209,9 +207,6 @@ def _scalar_rsub_(var, value):
     def _scalar_mul_(var, value):
         return _scalar_op_(var, value, 0.0)
 
-    def _scalar_div_(var, value):
-        return _scalar_op_(var, 1.0 / value, 0.0)
-
     def _binary_creator_(method_name,
                          op_type,
                          reverse=False,
@@ -241,7 +236,10 @@ def __impl__(self, other_var):
                 if op_type == 'elementwise_div' and self.dtype in _supported_int_dtype_:
                     self = astype(self, 'float32')
                 # here use `scale` replace `elementwise` to get better performance
-                # but only +, -, *, / can use this method
+                # but only +, -, * can use this method
+                # NOTE(chentianyu03): / can not use `scale` method，because the result of
+                # `scale` method (self*(1/other_var)) do not exactly equal with the result 
+                # of `elementwise_div` method.
                 if scalar_method is not None:
                     return scalar_method(self, other_var)
             else:
@@ -337,12 +335,8 @@ def __impl__(self, other_var):
         #  a*b == b*a. Do not need to reverse explicitly
         ('__rmul__',
          _binary_creator_('__rmul__', 'elementwise_mul', False, _scalar_mul_)),
-        ('__div__', _binary_creator_('__div__', 'elementwise_div', False,
-                                     _scalar_div_)),
         ('__truediv__', _binary_creator_('__truediv__', 'elementwise_div',
-                                         False, _scalar_div_)),
-        ('__rdiv__', _binary_creator_('__rdiv__', 'elementwise_div', True,
-                                      None)),
+                                         False, None)),
         ('__rtruediv__', _binary_creator_('__rtruediv__', 'elementwise_div',
                                           True, None)),
         ('__pow__', _binary_creator_('__pow__', 'elementwise_pow', False,

python/paddle/fluid/tests/unittests/test_tensor_scalar_type_promotion_dynamic.py

@@ -187,6 +187,13 @@ def test_tensor_div_scalar(self):
         c = paddle.full([2, 2, 2], 0.5, dtype="float32")
         self.check_operation(a, b, c, '/')
 
+        # tensor(float32) / scalar(int)
+        # this behavior should be equal to elementwise_div Op
+        a = paddle.to_tensor([99, 99, 99], dtype='float32')
+        b = 100
+        c = a / paddle.to_tensor([100, 100, 100], dtype='float32')
+        self.check_operation(a, b, c, '/')
+
         # tensor(int64) / scalar(float, .0)
         a = paddle.ones([2, 2, 2], dtype='int64')
         b = 2.0

python/paddle/fluid/tests/unittests/test_tensor_scalar_type_promotion_static.py

@@ -218,6 +218,12 @@ def test_tensor_div_scalar(self):
             c = paddle.full([2, 2, 2], 0.5, dtype="float32")
             self.check_operation(a, b, c, '/')
 
+            # this behavior should be equal to elementwise_div Op
+            a = paddle.full([2, 2, 2], 99, dtype="float32")
+            b = 100
+            c = a / paddle.full([2, 2, 2], 100, dtype="float32")
+            self.check_operation(a, b, c, '/')
+
         # tensor(int64) / scalar(float, .0)
         with program_guard(Program()):
             a = paddle.ones([2, 2, 2], dtype='int64')