比较与tf.compat.v1.train.MomentumOptimizer的功能差异
tf.compat.v1.train.MomentumOptimizer
tf.compat.v1.train.MomentumOptimizer(
learning_rate,
momentum,
use_locking=False,
name='Momentum',
use_nesterov=False
) -> Tensor
mindspore.nn.Momentum
class mindspore.nn.Momentum(
params,
learning_rate,
momentum,
weight_decay=0.0,
loss_scale=1.0,
use_nesterov=False
)(gradients) -> Tensor
更多内容详见mindspore.nn.Momentum。
差异对比
TensorFlow：实现Momentum算法的优化器。
MindSpore：MindSpore此API实现功能与TensorFlow基本一致。
分类 |
子类 |
TensorFlow |
MindSpore |
差异 |
|---|---|---|---|---|
参数 |
参数1 |
learning_rate |
learning_rate |
- |
参数2 |
momentum |
momentum |
- |
|
参数3 |
use_locking |
- |
TensorFlow中为是否在更新操作中使用锁，默认值：False。MindSpore无此参数 |
|
参数4 |
name |
- |
不涉及 |
|
参数5 |
use_nesterov |
use_nesterov |
- |
|
参数6 |
- |
params |
由Parameter组成的列表或字典组成的列表，TensorFlow中无此参数 |
|
参数7 |
- |
weight_decay |
权重衰减（L2 penalty），默认值：0.0，TensorFlow中无此参数 |
|
参数8 |
- |
loss_scale |
梯度缩放系数，默认值：1.0，TensorFlow中无此参数 |
|
参数9 |
- |
gradients |
参数params的梯度，TensorFlow中无此参数 |
代码示例
两API实现的功能基本一致。
# TensorFlow
import numpy as np
import tensorflow as tf
def forward_tensorflow_impl(input_np, label_np_onehot, output_channels, weight_np, bias_np, epoch, locking=False,
lr=0.1, momentum=0.0, use_nesterov=False, dtype=np.float32):
tf.compat.v1.disable_eager_execution()
input_tf = tf.constant(input_np, dtype=np.float32)
label = tf.constant(label_np_onehot)
if has_bias:
net = tf.compat.v1.layers.dense(inputs=input_tf, units=output_channels, use_bias=True,
kernel_initializer=tf.compat.v1.constant_initializer(
weight_np.transpose(1, 0), dtype=np.float32),
bias_initializer=tf.compat.v1.constant_initializer(bias_np,
dtype=np.float32)
)
else:
net = tf.compat.v1.layers.dense(inputs=input_tf, units=output_channels, use_bias=False,
kernel_initializer=tf.compat.v1.constant_initializer(
weight_np.transpose(1, 0), dtype=np.float32)
)
criterion = tf.compat.v1.losses.softmax_cross_entropy(onehot_labels=label,
logits=net,
reduction=tf.compat.v1.losses.Reduction.MEAN)
opt = tf.compat.v1.train.MomentumOptimizer(learning_rate=lr, momentum=momentum, use_locking=locking,
use_nesterov=use_nesterov).minimize(criterion)
init = tf.compat.v1.global_variables_initializer()
with tf.compat.v1.Session() as ss:
ss.run(init)
num = epoch
for _ in range(0, num):
criterion.eval()
ss.run(opt)
output = net.eval()
return output.astype(dtype)
input_np = np.array([[0.1, 0.2, 0.3],[0.4, 0.5, 0.6],[0.7, 0.8, 0.9]], dtype=np.float32)
weight_np = np.array([[0.1, 0.2, 0.3],[0.4, 0.5, 0.6],[0.7, 0.8, 0.9]], dtype=np.float32)
label_np = np.array([0, 2, 1])
label_np_onehot = np.zeros(shape=(3, 3)).astype(np.float32)
label_np_onehot[np.arange(3), label_np] = 1.0
has_bias = True
bias_np = np.array([0.1, 0.2, 0.3], dtype=np.float32)
input_channels = 3
output_channels = 3
epoch = 3
output = forward_tensorflow_impl(input_np, label_np_onehot, output_channels, weight_np, bias_np, epoch, locking=False,
lr=0.1, momentum=0.0, use_nesterov=False, dtype=np.float32)
print(output)
# [[0.28361297 0.5488669 0.72752017]
# [0.4602843 1.0305372 1.4191785 ]
# [0.6369556 1.5122076 2.1108367 ]]
# MindSpore
import numpy as np
from mindspore import Tensor
from mindspore.nn import Momentum as Momentum
from mindspore.nn import Dense, SoftmaxCrossEntropyWithLogits
from mindspore.nn import WithLossCell, TrainOneStepCell
def forward_mindspore_impl(input_np, weight_np, label_np_onehot, has_bias, bias_np, input_channels, output_channels,
epoch, learning_rate=0.1, weight_decay=0.0, momentum=0.0, loss_scale=1.0, use_nesterov=False):
input = Tensor(input_np)
weight = Tensor(weight_np)
label = Tensor(label_np_onehot)
if has_bias:
bias = Tensor(bias_np)
net = Dense(in_channels=input_channels, out_channels=output_channels,
weight_init=weight, bias_init=bias, has_bias=True)
else:
net = Dense(in_channels=input_channels, out_channels=output_channels,
weight_init=weight, has_bias=False)
criterion = SoftmaxCrossEntropyWithLogits(reduction='mean')
optimizer = Momentum(params=net.trainable_params(), learning_rate=learning_rate,
weight_decay=weight_decay,
momentum=momentum, loss_scale=loss_scale,
use_nesterov=use_nesterov)
net_with_criterion = WithLossCell(net, criterion)
train_network = TrainOneStepCell(net_with_criterion, optimizer)
train_network.set_train()
for _ in range(epoch):
train_network(input, label)
output = net(input)
return output.asnumpy()
input_np = np.array([[0.1, 0.2, 0.3],[0.4, 0.5, 0.6],[0.7, 0.8, 0.9]], dtype=np.float32)
weight_np = np.array([[0.1, 0.2, 0.3],[0.4, 0.5, 0.6],[0.7, 0.8, 0.9]], dtype=np.float32)
label_np = np.array([0, 2, 1])
label_np_onehot = np.zeros(shape=(3, 3)).astype(np.float32)
label_np_onehot[np.arange(3), label_np] = 1.0
has_bias = True
bias_np = np.array([0.1, 0.2, 0.3], dtype=np.float32)
input_channels = 3
output_channels = 3
epoch = 3
out = forward_mindspore_impl(input_np, weight_np, label_np_onehot, has_bias, bias_np, input_channels, output_channels,
epoch, learning_rate=0.1, weight_decay=0.0, momentum=0.0, loss_scale=1.0, use_nesterov=False)
print(out)
# [[0.28361297 0.5488669 0.72752017]
# [0.4602843 1.0305372 1.4191784 ]
# [0.6369556 1.5122076 2.1108367 ]]