BuildStrategy¶

class paddle.static. BuildStrategy ¶

BuildStrategy 使用户更方便地控制 ParallelExecutor 中计算图的建造方法，可通过设置 ParallelExecutor 中的 BuildStrategy 成员来实现此功能。

返回¶

BuildStrategy，一个BuildStrategy的实例。

代码示例¶

          import os
import paddle
import paddle.static as static

paddle.enable_static()

os.environ['CPU_NUM'] = str(2)
places = static.cpu_places()

data = static.data(name="x", shape=[None, 1], dtype="float32")
hidden = static.nn.fc(x=data, size=10)
loss = paddle.mean(hidden)
paddle.optimizer.SGD(learning_rate=0.01).minimize(loss)

build_strategy = static.BuildStrategy()
build_strategy.enable_inplace = True
build_strategy.memory_optimize = True
build_strategy.reduce_strategy = static.BuildStrategy.ReduceStrategy.Reduce
program = static.CompiledProgram(static.default_main_program())
program = program.with_data_parallel(loss_name=loss.name,
                                    build_strategy=build_strategy,
                                    places=places)

         

属性¶

debug_graphviz_path¶

str类型。表示以graphviz格式向文件中写入计算图的路径，有利于调试。默认值为空字符串。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.debug_graphviz_path = "./graph"

enable_sequential_execution¶

bool类型。如果设置为True，则算子的执行顺序将与算子定义的执行顺序相同。默认为False。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.enable_sequential_execution = True

fuse_broadcast_ops¶

bool类型。表明是否融合(fuse) broadcast ops。该选项指在Reduce模式下有效，使程序运行更快。默认为False。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.fuse_broadcast_ops = True

fuse_elewise_add_act_ops¶

bool类型。表明是否融合(fuse) elementwise_add_op和activation_op。这会使整体执行过程更快。默认为False。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.fuse_elewise_add_act_ops = True

fuse_relu_depthwise_conv¶

bool类型。表明是否融合(fuse) relu和depthwise_conv2d，节省GPU内存并可能加速执行过程。此选项仅适用于GPU设备。默认为False。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.fuse_relu_depthwise_conv = True

gradient_scale_strategy¶

paddle.static.BuildStrategy.GradientScaleStrategy 类型。在 ParallelExecutor 中，存在三种定义loss对应梯度( loss@grad )的方式，分别为 CoeffNumDevice, One 与 Customized。默认情况下， ParallelExecutor 根据设备数目来设置 loss@grad 。如果用户需要自定义 loss@grad ，可以选择 Customized 方法。默认为 CoeffNumDevice 。

代码示例

           import numpy
import os
import paddle
import paddle.static as static

paddle.enable_static()

use_cuda = True
place = paddle.CUDAPlace(0) if use_cuda else paddle.CPUPlace()
exe = static.Executor(place)

# NOTE: If you use CPU to run the program, you need
# to specify the CPU_NUM, otherwise, paddle will use
# all the number of the logic core as the CPU_NUM,
# in that case, the batch size of the input should be
# greater than CPU_NUM, if not, the process will be
# failed by an exception.
if not use_cuda:
    os.environ['CPU_NUM'] = str(2)
    places = static.cpu_places()
else:
    places = static.cuda_places()

data = static.data(name='X', shape=[None, 1], dtype='float32')
hidden = static.nn.fc(x=data, size=10)
loss = paddle.mean(hidden)
paddle.optimizer.SGD(learning_rate=0.01).minimize(loss)

exe.run(static.default_startup_program())

build_strategy = static.BuildStrategy()
build_strategy.gradient_scale_strategy = \
        static.BuildStrategy.GradientScaleStrategy.Customized
compiled_prog = static.CompiledProgram(
        static.default_main_program()).with_data_parallel(
                loss_name=loss.name, build_strategy=build_strategy,
                places=places)

dev_count =  len(places)
x = numpy.random.random(size=(10, 1)).astype('float32')
loss_grad = numpy.ones((dev_count)).astype("float32") * 0.01
loss_grad_name = loss.name+"@GRAD"
loss_data = exe.run(compiled_prog,
                    feed={"X": x, loss_grad_name : loss_grad},
                    fetch_list=[loss.name, loss_grad_name])

          

memory_optimize¶

bool类型或None。设为True时可用于减少总内存消耗，False表示不使用，None表示框架会自动选择使用或者不使用优化策略。当前，None意味着当GC不能使用时，优化策略将被使用。默认为None。

reduce_strategy¶

static.BuildStrategy.ReduceStrategy 类型。在 ParallelExecutor 中，存在两种参数梯度聚合策略，即 AllReduce 和 Reduce 。如果用户需要在所有执行设备上独立地进行参数更新，可以使用 AllReduce 。如果使用 Reduce 策略，所有参数的优化将均匀地分配给不同的执行设备，随之将优化后的参数广播给其他执行设备。默认值为 AllReduce 。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.reduce_strategy = static.BuildStrategy.ReduceStrategy.Reduce

remove_unnecessary_lock¶

bool类型。设置True会去除GPU操作中的一些锁操作， ParallelExecutor 将运行得更快，默认为True。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.remove_unnecessary_lock = True

sync_batch_norm¶

bool类型。表示是否使用同步的批正则化，即在训练阶段通过多个设备同步均值和方差。当前的实现不支持FP16训练和CPU。并且目前**仅支持**仅在一台机器上进行同步式批正则。默认为 False。

代码示例

           import paddle
import paddle.static as static

paddle.enable_static()

build_strategy = static.BuildStrategy()
build_strategy.sync_batch_norm = True