Merge pull request #15678 from jerrywgz/refine_softmax_with_cross_entropy

change default option related to softmax, test=develop

paddle/fluid/API.spec

@@ -86,7 +86,7 @@ paddle.fluid.layers.conv2d ArgSpec(args=['input', 'num_filters', 'filter_size',
 paddle.fluid.layers.conv3d ArgSpec(args=['input', 'num_filters', 'filter_size', 'stride', 'padding', 'dilation', 'groups', 'param_attr', 'bias_attr', 'use_cudnn', 'act', 'name'], varargs=None, keywords=None, defaults=(1, 0, 1, None, None, None, True, None, None))
 paddle.fluid.layers.sequence_pool ArgSpec(args=['input', 'pool_type', 'is_test'], varargs=None, keywords=None, defaults=(False,))
 paddle.fluid.layers.sequence_softmax ArgSpec(args=['input', 'use_cudnn', 'name'], varargs=None, keywords=None, defaults=(False, None))
-paddle.fluid.layers.softmax ArgSpec(args=['input', 'use_cudnn', 'name'], varargs=None, keywords=None, defaults=(True, None))
+paddle.fluid.layers.softmax ArgSpec(args=['input', 'use_cudnn', 'name'], varargs=None, keywords=None, defaults=(False, None))
 paddle.fluid.layers.pool2d ArgSpec(args=['input', 'pool_size', 'pool_type', 'pool_stride', 'pool_padding', 'global_pooling', 'use_cudnn', 'ceil_mode', 'name', 'exclusive'], varargs=None, keywords=None, defaults=(-1, 'max', 1, 0, False, True, False, None, True))
 paddle.fluid.layers.pool3d ArgSpec(args=['input', 'pool_size', 'pool_type', 'pool_stride', 'pool_padding', 'global_pooling', 'use_cudnn', 'ceil_mode', 'name', 'exclusive'], varargs=None, keywords=None, defaults=(-1, 'max', 1, 0, False, True, False, None, True))
 paddle.fluid.layers.adaptive_pool2d ArgSpec(args=['input', 'pool_size', 'pool_type', 'require_index', 'name'], varargs=None, keywords=None, defaults=('max', False, None))
@@ -128,7 +128,7 @@ paddle.fluid.layers.row_conv ArgSpec(args=['input', 'future_context_size', 'para
 paddle.fluid.layers.multiplex ArgSpec(args=['inputs', 'index'], varargs=None, keywords=None, defaults=None)
 paddle.fluid.layers.layer_norm ArgSpec(args=['input', 'scale', 'shift', 'begin_norm_axis', 'epsilon', 'param_attr', 'bias_attr', 'act', 'name'], varargs=None, keywords=None, defaults=(True, True, 1, 1e-05, None, None, None, None))
 paddle.fluid.layers.group_norm ArgSpec(args=['input', 'groups', 'epsilon', 'param_attr', 'bias_attr', 'act', 'data_layout', 'name'], varargs=None, keywords=None, defaults=(1e-05, None, None, None, 'NCHW', None))
-paddle.fluid.layers.softmax_with_cross_entropy ArgSpec(args=['logits', 'label', 'soft_label', 'ignore_index', 'numeric_stable_mode', 'return_softmax'], varargs=None, keywords=None, defaults=(False, -100, False, False))
+paddle.fluid.layers.softmax_with_cross_entropy ArgSpec(args=['logits', 'label', 'soft_label', 'ignore_index', 'numeric_stable_mode', 'return_softmax'], varargs=None, keywords=None, defaults=(False, -100, True, False))
 paddle.fluid.layers.smooth_l1 ArgSpec(args=['x', 'y', 'inside_weight', 'outside_weight', 'sigma'], varargs=None, keywords=None, defaults=(None, None, None))
 paddle.fluid.layers.one_hot ArgSpec(args=['input', 'depth'], varargs=None, keywords=None, defaults=None)
 paddle.fluid.layers.autoincreased_step_counter ArgSpec(args=['counter_name', 'begin', 'step'], varargs=None, keywords=None, defaults=(None, 1, 1))

paddle/fluid/operators/softmax_with_cross_entropy_op.cc

@@ -46,10 +46,10 @@ class SoftmaxWithCrossEntropyOpMaker
         .SetDefault(false);
     AddAttr<bool>(
         "numeric_stable_mode",
-        "(bool, default: false), A flag to indicate whether to use more "
+        "(bool, default: true), A flag to indicate whether to use more "
         "numerically stable algorithm. This flag is only valid when "
         "soft_label is false and GPU is used.")
-        .SetDefault(false);
+        .SetDefault(true);
     AddAttr<int>(
         "ignore_index",
         "(int, default -100), Specifies a target value that is ignored and"

python/paddle/fluid/layers/nn.py

@@ -1767,7 +1767,7 @@ def sequence_softmax(input, use_cudnn=False, name=None):
     return softmax_out
 
 
-def softmax(input, use_cudnn=True, name=None):
+def softmax(input, use_cudnn=False, name=None):
     """
     The input of the softmax operator is a tensor of any rank. The output tensor
     has the same shape as the input.
@@ -1795,7 +1795,8 @@ def softmax(input, use_cudnn=True, name=None):
     Args:
         input (Variable): The input variable.
         use_cudnn (bool): Use cudnn kernel or not, it is valid only when the cudnn \
-            library is installed.
+            library is installed. To improve numerical stablity, set use_cudnn to \
+            False by default. Default: False
         name (str|None): A name for this layer(optional). If set None, the layer
             will be named automatically. Default: None.
 
@@ -5753,7 +5754,7 @@ def softmax_with_cross_entropy(logits,
                                label,
                                soft_label=False,
                                ignore_index=kIgnoreIndex,
-                               numeric_stable_mode=False,
+                               numeric_stable_mode=True,
                                return_softmax=False):
     """
     **Softmax With Cross Entropy Operator.**
@@ -5817,7 +5818,7 @@ def softmax_with_cross_entropy(logits,
                                     When soft_label is True or CPU is used,
                                     the algorithm is always numerically stable.
                                     Note that the speed may be slower when use
-                                    stable algorithm. Default: False
+                                    stable algorithm. Default: True
         return_softmax (bool): A flag indicating whether to return the softmax
                                along with the cross entropy loss. Default: False