Python API for save/load variables (#5136)

* Python API for save/load variables

* Polish names

python/paddle/v2/framework/executor.py

@@ -19,11 +19,16 @@ class Executor(object):
 
     def run(self,
             program,
-            feed,
-            fetch_list,
+            feed=None,
+            fetch_list=None,
             feed_var_name='feed',
             fetch_var_name='fetch',
             scope=None):
+        if feed is None:
+            feed = {}
+        if fetch_list is None:
+            fetch_list = []
+
         if not isinstance(program, Program):
             raise TypeError()
 

python/paddle/v2/framework/framework.py

@@ -486,6 +486,11 @@ class Program(object):
         for block in self.blocks:
             block.sync_with_cpp()
 
+    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):

python/paddle/v2/framework/io.py

@@ -0,0 +1,143 @@
+import os
+
+from paddle.v2.framework.framework import Program, Parameter, g_program, \
+    Variable
+
+__all__ = [
+    'save_vars', 'save_params', 'save_persistables', 'load_vars', 'load_params',
+    'load_persistables'
+]
+
+
+def is_parameter(var):
+    return isinstance(var, Parameter)
+
+
+def is_persistable(var):
+    return var.persistable
+
+
+def _clone_var_in_block_(block, var):
+    assert isinstance(var, Variable)
+    return block.create_var(
+        name=var.name,
+        shape=var.shape,
+        dtype=var.data_type,
+        type=var.type,
+        lod_level=var.lod_level,
+        persistable=True)
+
+
+def save_vars(executor, dirname, program=None, vars=None, predicate=None):
+    """
+    Save variables to directory by executor.
+    
+    :param executor: executor that save variable
+    :param dirname: directory path
+    :param program: program. If vars is None, then filter all variables in this 
+    program which fit `predicate`. Default g_program.
+    :param predicate: The Predicate describes a callable that returns a variable
+    as a bool. If it returns true, the variables will be saved.
+    :param vars: variables need to be saved. If specify vars, program & predicate
+    will be ignored
+    :return: None
+    """
+    if vars is None:
+        if program is None:
+            program = g_program
+        if not isinstance(program, Program):
+            raise TypeError("program should be as Program type or None")
+
+        save_vars(
+            executor,
+            dirname=dirname,
+            vars=filter(predicate, program.list_vars()))
+    else:
+        save_program = Program()
+        save_block = save_program.global_block()
+        for each_var in vars:
+            new_var = _clone_var_in_block_(save_block, each_var)
+            save_block.append_op(
+                type='save',
+                inputs={'X': [new_var]},
+                outputs={},
+                attrs={'file_path': os.path.join(dirname, new_var.name)})
+        executor.run(save_program)
+
+
+def save_params(executor, dirname, program=None):
+    """
+    Save all parameters to directory with executor.
+    """
+    save_vars(
+        executor,
+        dirname=dirname,
+        program=program,
+        vars=None,
+        predicate=is_parameter)
+
+
+def save_persistables(executor, dirname, program=None):
+    """
+    Save all persistables to directory with executor.
+    """
+    save_vars(
+        executor,
+        dirname=dirname,
+        program=program,
+        vars=None,
+        predicate=is_persistable)
+
+
+def load_vars(executor, dirname, program=None, vars=None, predicate=None):
+    """
+    Load variables from directory by executor.
+    
+    :param executor: executor that save variable
+    :param dirname: directory path
+    :param program: program. If vars is None, then filter all variables in this 
+    program which fit `predicate`. Default g_program.
+    :param predicate: The Predicate describes a callable that returns a variable
+    as a bool. If it returns true, the variables will be loaded.
+    :param vars: variables need to be loaded. If specify vars, program & 
+    predicate will be ignored
+    :return: None
+    """
+    if vars is None:
+        if program is None:
+            program = g_program
+        if not isinstance(program, Program):
+            raise TypeError("program's type should be Program")
+
+        load_vars(
+            executor,
+            dirname=dirname,
+            vars=filter(predicate, program.list_vars()))
+    else:
+        load_prog = Program()
+        load_block = load_prog.global_block()
+        for each_var in vars:
+            assert isinstance(each_var, Variable)
+            new_var = _clone_var_in_block_(load_block, each_var)
+            load_block.append_op(
+                type='load',
+                inputs={},
+                outputs={"Out": [new_var]},
+                attrs={'file_path': os.path.join(dirname, new_var.name)})
+        executor.run(load_prog)
+
+
+def load_params(executor, dirname, program=None):
+    """
+    load all parameters from directory by executor.
+    """
+    load_vars(
+        executor, dirname=dirname, program=program, predicate=is_parameter)
+
+
+def load_persistables(executor, dirname, program=None):
+    """
+    load all persistables from directory by executor.
+    """
+    load_vars(
+        executor, dirname=dirname, program=program, predicate=is_persistable)

python/paddle/v2/framework/tests/.gitignore

@@ -1 +1,2 @@
 image/
+fit_a_line.model/

python/paddle/v2/framework/tests/test_fit_a_line.py

@@ -4,6 +4,7 @@ import paddle.v2.framework.core as core
 import paddle.v2.framework.optimizer as optimizer
 
 from paddle.v2.framework.framework import Program, g_program
+from paddle.v2.framework.io import save_persistables, load_persistables
 from paddle.v2.framework.executor import Executor
 
 import numpy as np
@@ -51,6 +52,8 @@ exe.run(init_program, feed={}, fetch_list=[])
 
 PASS_NUM = 100
 for pass_id in range(PASS_NUM):
+    save_persistables(exe, "./fit_a_line.model/", program=program)
+    load_persistables(exe, "./fit_a_line.model/", program=program)
     for data in train_reader():
         x_data = np.array(map(lambda x: x[0], data)).astype("float32")
         y_data = np.array(map(lambda x: x[1], data)).astype("float32")