# Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import collections import contextlib import re import numpy as np import proto.framework_pb2 as framework_pb2 from . import core __all__ = [ 'Block', 'Variable', 'Program', 'Operator', 'default_startup_program', 'default_main_program', 'program_guard', 'switch_startup_program', 'switch_main_program', 'get_var', ] EMPTY_VAR_NAME = core.kEmptyVarName() TEMP_VAR_NAME = core.kTempVarName() GRAD_VAR_SUFFIX = core.kGradVarSuffix() ZERO_VAR_SUFFIX = core.kZeroVarSuffix() def grad_var_name(var_name): """ return gradient name for a certain var name """ return var_name + GRAD_VAR_SUFFIX def unique_name(prefix): """ Generate unique names with prefix Args: prefix(str): The prefix of return string Returns(str): A unique string with the prefix """ uid = core.unique_integer(prefix) # unique during whole process. return "_".join([prefix, str(uid)]) def convert_np_dtype_to_dtype_(np_dtype): """ Convert the data type in numpy to the data type in Paddle Args: np_dtype(np.dtype): the data type in numpy Returns(core.VarType): the data type in Paddle """ dtype = np.dtype(np_dtype) if dtype == np.float32: return core.VarType.FP32 elif dtype == np.float64: return core.VarType.FP64 elif dtype == np.float16: return core.VarType.FP16 elif dtype == np.int32: return core.VarType.INT32 elif dtype == np.int16: return core.VarType.INT16 elif dtype == np.int64: return core.VarType.INT64 elif dtype == np.bool: return core.VarType.BOOL else: raise ValueError("Not supported numpy dtype " + str(dtype)) def dtype_is_floating(dtype): """ Check the data type is floating or not. Args: dtype(np.dtype|core.DataType): data type. Could be numpy format or Paddle format Returns(bool): True if data type is a float value """ if not isinstance(dtype, core.VarType): dtype = convert_np_dtype_to_dtype_(dtype) return dtype in [core.VarType.FP16, core.VarType.FP32, core.VarType.FP64] def _debug_string_(proto, throw_on_error=True): """ Get the debug string of a protobuf message. The message could be not initialized. Args: proto(google.protobuf.message.Message): The protobuf message throw_on_error(bool): True if raise an error when the protobuf message is not initialized. Returns(str): The debug string of the protobuf message """ error_fields = list() if not proto.IsInitialized(error_fields) and throw_on_error: raise ValueError("{0} are not initialized.\nThe message is {1}:\n". format(error_fields, proto)) return proto.__str__() class Variable(object): """ Python variable. Every input and output of an operator is a variable. Every variable belongs to a block. The variable has a name and two variables in different blocks could have the same name. There are many kinds of variables. Please reference the framework.proto for details. Notes: The constructor of Variable should not be invoked directly. Please use `Block.create_var` to create a variable. >>> cur_program = Program() >>> cur_block = cur_program.current_block() >>> new_variable = cur_block.create_var( >>> name="X", shape=[-1, 23, 48], dtype='float32') Args: block(Block): The associated block. It will be passed by `Block.create_var` automatically. type(core.VarDesc.VarType): Variable type. Please reference the framework.proto for details. shape(tuple|list|None): The shape of variable. -1 means the batch size. Some kinds of variable do not contain shape, just set it to None. dtype(np.dtype|core.DataType|str): The data type of variable. lod_level(int): The level of lod tensor. 0 means there is not a time series data. persistable(bool): True if the variable should be saved as check point. Defaults to False. stop_gradient(bool): True if the variable will stop to calculate gradients when backward. Defaults to False. """ def __init__(self, block, type=core.VarDesc.VarType.LOD_TENSOR, name=None, shape=None, dtype=None, lod_level=None, persistable=None, error_clip=None, stop_gradient=False, **kwargs): self.block = block self.error_clip = error_clip if name is None: name = Variable._unique_var_name_() is_new_var = False self.desc = self.block.desc.find_var(name) if self.desc is None: self.desc = self.block.desc.var(name) is_new_var = True if is_new_var: self.desc.set_type(type) elif self.desc.type() != type: raise ValueError("Variable {0} has been created before. The " "previous type is {1}; the new type is {2}. They" " are not matched".format(self.name, self.desc.type(), type)) if shape is not None: if is_new_var: self.desc.set_shape(shape) else: old_shape = self.shape shape = tuple(shape) if shape != old_shape: raise ValueError( "Variable {0} has been created before. the previous " "shape is {1}; the new shape is {2}. They are not " "matched.".format(self.name, old_shape, shape)) if dtype is not None: if not isinstance(dtype, core.VarType): dtype = convert_np_dtype_to_dtype_(dtype) if is_new_var: self.desc.set_dtype(dtype) else: old_dtype = self.dtype if dtype != old_dtype: raise ValueError("Variable {0} has been created before. " "The previous data type is {1}; the new " "data type is {2}. They are not " "matched.".format(self.name, old_dtype, dtype)) if lod_level is not None: if is_new_var: self.desc.set_lod_level(lod_level) else: if lod_level != self.lod_level: raise ValueError("Variable {0} has been created before. " "The previous lod_level is {1}; the new " "lod_level is {2}. They are not " "matched".format(self.name, self.lod_level, lod_level)) if persistable is not None: if is_new_var: self.desc.set_persistable(persistable) else: if persistable != self.persistable: raise ValueError( "Variable {0} has been created before." "The previous persistable is {1}; the new " "persistable is {2}. They are not matched".format( self.name, self.persistable, persistable)) self.block.vars[name] = self self.op = None self.stop_gradient = stop_gradient def __str__(self): return self.to_string(True) def to_string(self, throw_on_error, with_details=False): """ Get debug string. Args: throw_on_error(bool): True if raise an exception when self is not intialized. with_details(bool): more details about variables and parameters (e.g. trainable, optimize_attr, ...) will be printed when with_details is True Returns(str): The debug string. """ assert isinstance(throw_on_error, bool) and isinstance(with_details, bool) protostr = self.desc.serialize_to_string() proto = framework_pb2.VarDesc.FromString(str(protostr)) res_str = _debug_string_(proto, throw_on_error) if with_details: additional_attr = ("error_clip", "stop_gradient") for attr_name in additional_attr: res_str += "%s: %s\n" % (attr_name, str(getattr(self, attr_name))) return res_str __repr__ = __str__ def set_desc(self, input): self.desc = input @property def persistable(self): return self.desc.persistable() @persistable.setter def persistable(self, p): self.desc.set_persistable(p) @property def name(self): return self.desc.name() @property def shape(self): # convert to tuple, make it as same as numpy API. return tuple(self.desc.shape()) @property def dtype(self): return self.desc.dtype() @property def lod_level(self): return self.desc.lod_level() @property def type(self): return self.desc.type() @staticmethod def _unique_var_name_(): prefix = "_generated_var" uid = core.unique_integer(prefix) # unique during whole process. return "_".join([prefix, str(uid)]) def set_error_clip(self, error_clip): self.error_clip = error_clip def get_all_op_protos(): """ Get all registered op proto from PaddlePaddle C++ end. Returns(list): list of OpProto """ protostrs = core.get_all_op_protos() ret_values = [] for pbstr in protostrs: op_proto = framework_pb2.OpProto.FromString(str(pbstr)) ret_values.append(op_proto) return ret_values class OpProtoHolder(object): """ A global variable to hold all OpProtos from C++ as a map """ @classmethod def instance(cls): if not hasattr(cls, '_instance'): cls._instance = cls() return cls._instance def __init__(self): assert not hasattr( self.__class__, '_instance'), 'Please use `instance()` to get OpProtoHolder opject!' op_protos = get_all_op_protos() self.op_proto_map = {} for proto in op_protos: self.op_proto_map[proto.type] = proto def get_op_proto(self, type): """ Get OpProto by a type string. Args: type(str): The type that operator registered in C++ side. Returns(framework_pb2.OpProto): The OpProto """ if type not in self.op_proto_map: raise ValueError("Operator \"%s\" has not been registered." % type) return self.op_proto_map[type] class Operator(object): """ Python Operator class. The operator represents the build in instructs in a Block. Users can use the build in instructs to describe their neural network. """ def __init__(self, block, desc, type=None, inputs=None, outputs=None, attrs=None): """ Constructor. Notes: The constructor of operator should not be invoked directly. Use Block.append_op or Block.prepend_op instead. >>> cur_program = Program() >>> cur_block = cur_program.current_block() >>> # var1 += var2 + var3 >>> cur_block.append_op(type="sum", >>> inputs={"X": [var1, var2, var3]}, >>> outputs={"Out": [var1]}) Args: block(Block): The block has the current operator. desc(core.OpDesc): The protobuf description. type(str): The type of operator. inputs(dict): The input dictionary. Key is the input parameter name. Value is a list of variables. outputs(dict): The output dictionary which has the same format with inputs. attrs(dict): The attributes dictionary. Key is attribute name. Value is the attribute value. The attribute type should be as same as the type registered in C++ """ self.block = block self.desc = desc self.attrs = attrs if len(self.desc.type()) != 0: return if type is None: raise ValueError( "`type` to initilized an Operator can not be None.") self.desc.set_type(type) proto = OpProtoHolder.instance().get_op_proto(type) def find_name(var_list, name): for var_name in var_list: if var_list[var_name] is not None and var_name == name: return True return False if inputs is not None: for in_proto in proto.inputs: found = find_name(inputs, in_proto.name) assert found or in_proto.dispensable, "Input {} not found".format( in_proto.name) if found: in_args = inputs[in_proto.name] if not isinstance(in_args, list): in_args = [in_args] if not in_proto.duplicable and len(in_args) > 1: raise ValueError( "Input %s expects only one input, but %d are given." % (in_proto.name, len(in_args))) in_arg_names = [] for arg in in_args: if isinstance(arg, basestring): in_arg_names.append(arg) else: in_arg_names.append(arg.name) self.desc.set_input(in_proto.name, in_arg_names) else: self.desc.set_input(in_proto.name, []) if outputs is not None: given = set() need = set() for n in outputs: given.add(n) for m in proto.outputs: need.add(m.name) if not given == need: raise ValueError(("Incorrect setting for output(s) of " "operator \"%s\". Need: [%s] Given: [%s]") % (type, ", ".join(str(e) for e in need), ", ".join(str(e) for e in given))) for out_proto in proto.outputs: out_args = outputs[out_proto.name] if not isinstance(out_args, list): out_args = [out_args] if not out_proto.duplicable and len(out_args) > 1: raise ValueError( "Output %s expects only one output, but %d are given." % (out_proto.name, len(out_args))) out_arg_names = [] for arg in out_args: out_arg_names.append(arg.name) arg.op = self self.desc.set_output(out_proto.name, out_arg_names) if attrs is not None: if not isinstance(attrs, dict): raise TypeError("'attrs' should be a dict.") for attr in proto.attrs: attr_name = attr.name if (not attr_name in attrs) or (attrs[attr_name] is None): continue if isinstance(attrs[attr_name], Block): self.desc.set_block_attr(attr_name, attrs[attr_name].desc) elif isinstance(attrs[attr_name], core.BlockDesc) or \ isinstance(attrs[attr_name], core.ProgramDesc): self.desc.set_serialized_attr( attr_name, attrs[attr_name].serialize_to_string()) else: self.desc.set_attr(attr_name, attrs[attr_name]) self.desc.check_attrs() no_kernel_op_set = { 'feed', 'fetch', 'save', 'load', 'recurrent', 'rnn_memory_helper_grad', 'conditional_block', 'while', 'send', 'recv', 'listen_and_serv', 'parallel_do', 'save_combine', 'load_combine' } if type not in no_kernel_op_set: self.desc.infer_var_type(self.block.desc) self.desc.infer_shape(self.block.desc) def to_string(self, throw_on_error): """ To debug string. Args: throw_on_error(bool): raise exception when self is not initialized when throw_on_error is True Returns(str): The debug string. """ protostr = self.desc.serialize_to_string() proto = framework_pb2.OpDesc.FromString(str(protostr)) return _debug_string_(proto, throw_on_error) def __str__(self): return self.to_string(True) __repr__ = __str__ @property def type(self): return self.desc.type() def input(self, name): """ Get input arguments by the input parameter name Args: name(str): The input parameter name Returns(list): return the list of argument names associated with the specific parameter name. """ return self.desc.input(name) @property def input_names(self): """ Get all input parameter names Returns(list): return a list of input parameter names """ return self.desc.input_names() def output(self, name): """ Get output arguments by the output parameter name Args: name(str): The output parameter name Returns(list): return the list of argument names associated with the specific parameter name. """ return self.desc.output(name) @property def output_names(self): """ Get all output parameter names Returns(list): return a list of output parameter names """ return self.desc.output_names() @property def idx(self): """ Return the array index of current operator. Returns(int): The array index in block.ops array Raises: ValueError: when the operator is not found. """ for i, op in enumerate(self.block.ops): if op == self: return i raise ValueError( "Can't find op itself in it's block. It could be a bug of Paddle.") def has_attr(self, name): """ operator has the attribute with name or not. Args: name(str): the attribute name Returns(bool): True if has this attribute. """ return self.desc.has_attr(name) def attr_type(self, name): """ Get the type of attribute by attribute name Args: name(str): the attribute name Returns(core.AttrType): the attribute type """ return self.desc.attr_type(name) @property def attr_names(self): """ Get all attribute names Returns(list): The list of attribute name """ return self.desc.attr_names() def attr(self, name): """ Get attribute by name Args: name(str): the attribute name Returns(bool|int|str|float|list): The attribute value. The return value can be any valid attribute type. """ return self.desc.attr(name) def block_attr(self, name): """ Get the block attribute by name Args: name(str): the attribute name Returns(int): the block index """ return self.desc.block_attr(name) class Block(object): def __init__(self, program, idx): self.desc = program.desc.block(idx) self.vars = dict() # var_name --> var self.ops = collections.deque() # operator list self.program = program self.removed_vars = dict() def __str__(self): return self.to_string(True) def to_string(self, throw_on_error, with_details=False): """ To debug string. Args: throw_on_error(bool): raise exception when self is not initialized when throw_on_error is True with_details(bool): more details about variables and parameters (e.g. trainable, optimize_attr, ...) will be printed when with_details is True Returns(str): The debug string. """ assert isinstance(throw_on_error, bool) and isinstance(with_details, bool) if with_details: re_add_indent = re.compile(r"\n(.)") res_str = "blocks {\n idx: %d\n parent_idx: %d" % ( self.idx, self.parent_idx) for var in self.vars.itervalues(): res_str += "\n vars {\n %s }" % re_add_indent.sub( r"\n \1", var.to_string(throw_on_error, with_details)) for op in self.ops: res_str += "\n ops {\n %s }" % re_add_indent.sub( r"\n \1", op.to_string(throw_on_error)) res_str += "\n}" else: protostr = self.desc.serialize_to_string() proto = framework_pb2.BlockDesc.FromString(str(protostr)) res_str = _debug_string_(proto, throw_on_error) return res_str __repr__ = __str__ @property def parent_idx(self): return self.desc.parent @property def idx(self): return self.desc.id def var(self, name): if not isinstance(name, basestring): raise TypeError() v = self.vars.get(name, None) if v is None: raise ValueError("var %s not in this block" % name) return v def var_recursive(self, name): if self.has_var(name): return self.var(name) else: if self.idx == 0: raise ValueError("var %s is not in block(%d) nor its parents." % name, self.idx) else: parent_block = self.program.block(self.parent_idx) return parent_block.var_recursive(name) def all_parameters(self): return list(self.iter_parameters()) def iter_parameters(self): return (item[1] for item in self.vars.iteritems() if isinstance(item[1], Parameter)) def create_var(self, *args, **kwargs): var = Variable(self, *args, **kwargs) if 'initializer' in kwargs: kwargs['initializer'](var, self) return var def has_var(self, name): return name in self.vars def create_parameter(self, *args, **kwargs): global_block = self.program.global_block() param = Parameter(global_block, *args, **kwargs) if 'initializer' in kwargs: kwargs['initializer'](param, self) return param def append_op(self, *args, **kwargs): op_desc = self.desc.append_op() op = Operator(self, op_desc, *args, **kwargs) self.ops.append(op) return op def delete_ops(self, ops): # remove from cpp # FIXME(typhoonzero): remove only the first occuracy. try: start = list(self.ops).index(ops[0]) end = list(self.ops).index(ops[-1]) except Exception, e: raise e self.desc.remove_op(start, end + 1) def slice_ops(self, start, end): return list(self.ops)[start:end] def prepend_op(self, *args, **kwargs): op_desc = self.desc.prepend_op() op = Operator(self, op_desc, *args, **kwargs) self.ops.appendleft(op) return op def sync_with_cpp(self): # sync variables from cpp for var in self.desc.all_vars(): if not self.has_var(var.name()): self.create_var(name=var.name(), desc=var, type=var.type()) # sync operators from cpp ops_in_cpp = [] for op_idx in range(0, self.desc.op_size()): ops_in_cpp.append(self.desc.op(op_idx)) if len(self.ops) != 0: first_op_in_python = self.ops[0].desc last_op_in_python = self.ops[len(self.ops) - 1].desc start_index = None end_index = None for index in range(len(ops_in_cpp)): if first_op_in_python == ops_in_cpp[index]: start_index = index if last_op_in_python == ops_in_cpp[index]: end_index = index assert start_index is not None assert end_index is not None assert start_index <= end_index else: start_index = 0 end_index = -1 # sync ops append to the head of cpp_ops for index in range((start_index - 1 - 1), -1, -1): op_desc = ops_in_cpp[index] op = Operator(self, op_desc) self.ops.appendleft(op) # sync ops append to the end of cpp_ops for index in range((end_index + 1), len(ops_in_cpp)): op_desc = ops_in_cpp[index] op = Operator(self, op_desc) self.ops.append(op) assert len(self.ops) == len(ops_in_cpp) for index in range(len(self.ops)): assert self.ops[index].desc == ops_in_cpp[index] def copy_param_info_from(self, other): """ Copy the information of parameters from other block Args: other(Block): other block Returns: None """ if not isinstance(other, Block): raise TypeError("copy_param_info_from should be invoked with Block") for p in other.iter_parameters(): assert isinstance(p, Parameter) v = self.vars.get(p.name, None) if v is None: raise ValueError("copy_param_info_from should be invoked with " "same topology") assert isinstance(v, Variable) new_p = Parameter( block=self, shape=v.shape, dtype=v.dtype, type=v.type, lod_level=v.lod_level, stop_gradient=p.stop_gradient, trainable=p.trainable, optimize_attr=p.optimize_attr, regularizer=p.regularizer, gradient_clip_attr=p.gradient_clip_attr, error_clip=p.error_clip, name=v.name) self.vars[new_p.name] = new_p class Program(object): def __init__(self): self.desc = core.ProgramDesc() self.blocks = [Block(self, 0)] self.current_block_idx = 0 self._seed = 0 def __str__(self): return self.to_string(True) def to_string(self, throw_on_error, with_details=False): """ To debug string. Args: throw_on_error(bool): raise exception when self is not initialized when throw_on_error is True with_details(bool): more details about variables and parameters (e.g. trainable, optimize_attr, ...) will be printed when with_details is True Returns(str): The debug string. """ assert isinstance(throw_on_error, bool) and isinstance(with_details, bool) if with_details: res_str = "" for block in self.blocks: res_str += block.to_string(throw_on_error, with_details) else: protostr = self.desc.serialize_to_string() proto = framework_pb2.ProgramDesc.FromString(str(protostr)) res_str = _debug_string_(proto, throw_on_error) return res_str def get_desc(self): return self.desc def clone(self): p = Program() p.desc = core.ProgramDesc(self.desc) p.blocks = [Block(p, i) for i in xrange(self.desc.num_blocks())] p.sync_with_cpp() p.copy_param_info_from(self) return p def prune(self, targets): if not isinstance(targets, list): targets = [targets] targets_idx = [] for t in targets: if not isinstance(t, Operator): if isinstance(t, Variable): t = t.op else: raise ValueError(("All targets of prune() can only be " "Variable or Operator.")) targets_idx.append([t.block.idx, t.idx]) res = Program() res.desc = core.prune(self.desc, targets_idx) res.blocks = [Block(res, i) for i in xrange(res.desc.num_blocks())] res.sync_with_cpp() return res def inference_optimize(self): res = Program() res.desc = core.inference_optimize(self.desc) res.blocks = [Block(res, i) for i in xrange(res.desc.num_blocks())] res.sync_with_cpp() return res @staticmethod def parse_from_string(binary_str): p = Program() p.desc = core.ProgramDesc(binary_str) p.blocks = [Block(p, i) for i in xrange(p.desc.num_blocks())] p.sync_with_cpp() return p @property def random_seed(self): return self._seed @random_seed.setter def random_seed(self, seed): if not isinstance(seed, int): raise ValueError("Seed must be a integer.") self._seed = seed def __repr__(self): return str(self) def global_block(self): return self.blocks[0] def block(self, index): return self.blocks[index] def current_block(self): return self.blocks[self.current_block_idx] def append_backward(self, target, no_grad_set=None): """ return map(param_name -> (grad_name, block_index, op_index)) """ assert isinstance(target, Variable) if no_grad_set is None: no_grad_set = set() try: param_to_grad_info = self.desc.append_backward(target.desc, no_grad_set) except Exception as e: raise core.EnforceNotMet( str(e) + "\nCurrent protobuf is\n{0}".format( self.to_string(False))) self.sync_with_cpp() return param_to_grad_info def create_block(self, parent_idx=None): new_block_idx = len(self.blocks) parent = self.current_block() if parent_idx is None else self.block( parent_idx) self.desc.append_block(parent.desc) self.current_block_idx = new_block_idx self.blocks.append(Block(self, self.current_block_idx)) return self.current_block() def rollback(self): self.current_block_idx = self.current_block().parent_idx def sync_with_cpp(self): for block_idx in range(len(self.blocks), self.desc.num_blocks()): self.blocks.append(Block(self, block_idx)) for block in self.blocks: block.sync_with_cpp() def copy_param_info_from(self, other): """ Copy the information of parameters from other program. Args: other(Program): Other program Returns: None """ if not isinstance(other, Program): raise TypeError("copy_param_info_from should be invoked with " "Program") if len(self.blocks) != len(other.blocks): raise ValueError("copy_param_info_from should be invoked with two " "program, with represent the same topology") self.global_block().copy_param_info_from(other.global_block()) def list_vars(self): for each_block in self.blocks: for each_var in each_block.vars.itervalues(): yield each_var class Parameter(Variable): def __init__(self, block, shape, dtype, **kwargs): if shape is None or dtype is None: raise ValueError("Parameter must set shape and dtype") if len(shape) == 0: raise ValueError("Parameter shape cannot be empty") for each in shape: if each < 0: raise ValueError("Parameter shape should not be related with " "batch-size") Variable.__init__( self, block, persistable=True, shape=shape, dtype=dtype, **kwargs) self.trainable = kwargs.get('trainable', True) self.optimize_attr = kwargs.get('optimize_attr', {'learning_rate': 1.0}) self.regularizer = kwargs.get('regularizer', None) self.gradient_clip_attr = kwargs.get('gradient_clip_attr', None) def __str__(self): return self.to_string(True) def to_string(self, throw_on_error, with_details=False): """ To debug string. Args: throw_on_error(bool): raise exception when self is not initialized when throw_on_error is True with_details(bool): more details about variables and parameters (e.g. trainable, optimize_attr, ...) will be printed when with_details is True Returns(str): The debug string. """ assert isinstance(throw_on_error, bool) and isinstance(with_details, bool) if with_details: res_str = Variable.to_string(self, throw_on_error, True) additional_attr = ("trainable", "optimize_attr", "regularizer", "gradient_clip_attr") for attr_name in additional_attr: res_str += "%s: %s\n" % (attr_name, str(getattr(self, attr_name))) else: res_str = Variable.to_string(self, throw_on_error, False) return res_str __repr__ = __str__ # program is a global instance. _main_program_ = Program() _startup_program_ = Program() def default_startup_program(): """ Get default startup program. In startup program, Paddle will initialize parameters, initialize nccl handle, etc. Returns: Program: startup program """ return _startup_program_ def default_main_program(): """ Get default main program. The main program is used for training or testing. Returns: Program: main program """ return _main_program_ def switch_main_program(program): """ Switch the main program to a new program. Args: program(Program): The new main program Returns: Program: The previous main program """ global _main_program_ prev_program = _main_program_ _main_program_ = program return prev_program def switch_startup_program(program): """ Switch the startup program to a new program Args: program(Program): The new startup program Returns: Program: The previous startup program """ global _startup_program_ prev_program = _startup_program_ _startup_program_ = program return prev_program @contextlib.contextmanager def program_guard(main_program, startup_program=None): """ Switch program with `with` statement Examples: >>> with program_guard(Program()): >>> data = fluid.layers.data(...) >>> hidden = fluid.layers.fc(...) Args: main_program(Program): New main program inside `with` statement startup_program(Program): New startup program inside `with` statement. None means do not change startup program. Returns: None """ if not isinstance(main_program, Program): raise TypeError("main_program should be Program") main_program = switch_main_program(main_program) if startup_program is not None: if not isinstance(startup_program, Program): raise TypeError("startup_program should be Program") startup_program = switch_startup_program(startup_program) yield switch_main_program(main_program) if startup_program is not None: switch_startup_program(startup_program) def get_var(name, program=None): """ Get a variable by name from the global block of a program Args: name(str): name of the variable program(Program|None): program object. If None, default_global_program() will be used. Returns: Variable """ if program is None: program = default_main_program() assert isinstance(name, str) assert isinstance(name, Program) return program.global_block().var(name)