utils.py

# Copyright (c) 2021 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 os
import copy
import paddle
import threading
import numpy as np
import warnings
import logging
from functools import reduce

import paddle.fluid.core as core
from paddle.framework.io import _to_LodTensor
from paddle.distributed.fleet.meta_optimizers.common import OpRole
from paddle.fluid.io import is_parameter, is_belong_to_optimizer


def is_valid_list_index(list, index):
    if index >= -len(list) and index < len(list):
        return True
    else:
        return False


def is_dim_shard(mapping):
    if mapping != -1:
        return True
    else:
        return False


def is_dim_replicate(mapping):
    if mapping == -1:
        return True
    else:
        return False


def compute_compatible_dim_mapping(dim_mappings):
    if not dim_mappings:
        return None
    compatible_mapping = dim_mappings[0]
    for mapping in dim_mappings:
        if compatible_mapping == -1:
            compatible_mapping = mapping
        elif mapping == -1:
            continue
        elif compatible_mapping == mapping:
            continue
        else:
            return None
    return compatible_mapping


def compute_compatible_dims_mapping(dims_mapping_list):
    if not dims_mapping_list:
        return None
    length = len(dims_mapping_list[0])
    for dims_mapping in dims_mapping_list:
        assert dims_mapping is not None, \
            "Dims mapping must not be None for compatible computation"
        assert len(dims_mapping) == length, \
            "The length of dims_mapping in list must be same for compatible computation."
    compatible_result = []
    for dim_mappings in zip(*dims_mapping_list):
        compatible_dim_mapping = compute_compatible_dim_mapping(
            list(dim_mappings))
        if compatible_dim_mapping is None:
            return None
        compatible_result.append(compatible_dim_mapping)
    return compatible_result


def compute_compatible_process_mesh(process_mesh_list):
    compatible_process_mesh = None
    if not process_mesh_list:
        return compatible_process_mesh
    for process_mesh in process_mesh_list:
        if process_mesh is not None:
            if compatible_process_mesh is None or compatible_process_mesh == process_mesh:
                compatible_process_mesh = process_mesh
            else:
                return None
    return compatible_process_mesh


def compute_compatible_and_update_dim_mapping(dims_mapping_list, index_list):
    assert len(dims_mapping_list) == len(index_list)
    changed = False
    dim_mappings = []
    for i in range(len(dims_mapping_list)):
        assert is_valid_list_index(dims_mapping_list[i], index_list[i])
        dim_mappings.append(dims_mapping_list[i][index_list[i]])
    compatible_dim_mapping = compute_compatible_dim_mapping(dim_mappings)
    if compatible_dim_mapping is None:
        return False
    for i in range(len(dims_mapping_list)):
        if compatible_dim_mapping != dims_mapping_list[i][index_list[i]]:
            dims_mapping_list[i][index_list[i]] = compatible_dim_mapping
            changed = True
    return changed


def append_distributed_attr_suffix(name):
    """
    Append auto parallel suffix for distributed attribute name.
    """
    return name + core.kAutoParallelSuffix()


def remove_distributed_attr_suffix(name):
    """
    Remove auto parallel suffix from distributed attribute name.
    """
    return name.strip(core.kAutoParallelSuffix())


def check_distributed_attr_for_program(program, dist_context=None):
    from .dist_context import get_default_distributed_context
    if dist_context is None:
        dist_context = get_default_distributed_context()
    assert dist_context.is_initialized_for_program(), \
        "Distributed attributes must be initialized before check."
    for block in program.blocks:
        for tensor in block.vars.values():
            dist_tensor = dist_context.get_dist_tensor_for_graph(tensor)
            tensor_dist_attr = dist_context.get_tensor_dist_attr_for_program(
                tensor)
            if (tensor_dist_attr is not None) and (not dist_tensor.is_valid()):
                return False
        for op in block.ops:
            dist_op = dist_context.get_dist_op_for_graph(tensor)
            op_dist_attr = dist_context.get_op_dist_attr_for_program(op)
            if (op_dist_attr is not None) and (not dist_op.is_valid()):
                return False
    return True


def print_program_with_dist_attr(program, dist_context=None):
    """
    This function reuses the original program output ability with a distributed context.
    Using lock can avoid multiple threads change the default distributed context simultaneously.
    """
    lock = threading.Lock()
    lock.acquire()
    from .dist_context import get_default_distributed_context
    from .dist_context import set_default_distributed_context
    if dist_context is None:
        dist_context = get_default_distributed_context()
        print(program)
    else:
        original_default_context = get_default_distributed_context()
        set_default_distributed_context(dist_context)
        print(program)
        set_default_distributed_context(original_default_context)
    lock.release()


def _get_comm_group(processes, shape, axis, rank):
    """
    Given a rank and the processes mesh the rank belongs to,  
    compute the communication peers of the rank based on the give axis in the mesh.

    Example: 16 processes managed in a 4-Dimensinal mesh with shape of [2, 2, 2, 2].
    the rank communication peers of rank 0 (included) are following:
    in axis 0: [0, 1]
    in axis 1: [0, 2]
    in axis 2: [0, 4]
    in axis 3: [0, 8]
    """

    # NOTE _linear_idx2coordinate assume processes mesh start with 0 and continuous
    # tricks to support processes mesh when it is not start with 0 or continuous
    assert rank in processes, "rank [{}] is NOT in processes group {}".format(
        rank, processes)
    rank_relatvie = processes.index(rank)
    coordinate = _linear_idx2coordinate(shape, rank_relatvie)
    coordinates_in_group = [coordinate[:] for i in range(shape[axis])]

    # select comm group
    for i in range(shape[axis]):
        coordinates_in_group[i][axis] = i

    ranks_in_group_relative = [
        _coordinate2linear_idx(shape, coordinate)
        for coordinate in coordinates_in_group
    ]
    ranks_in_group = [processes[idx] for idx in ranks_in_group_relative]

    return sorted(ranks_in_group)


def _get_idx_in_axis(processes, shape, axis, rank):
    """
    Given a rank and the processes mesh the rank belongs to,  
    compute the index of the rank in given axis.

    Example: 27 processes managed in a 3-Dimensinal mesh with shape of [3, 3, 3].
    the index of rank 22 are:
    in axis 0: 1
    in axis 1: 1
    in axis 2: 2
    """

    # NOTE _linear_idx2coordinate assume processes mesh start with 0 and continuous
    #  tricks to support processes mesh when it is not start with 0 or continuous
    rank_relatvie = processes.index(rank)
    coordinate = _linear_idx2coordinate(shape, rank_relatvie)
    return coordinate[axis]


def _coordinate2linear_idx(mesh_shape, coordinate):
    """
    convert a coordinate in multidimensional mesh space into a scala idx in linear space.

    it use Row-major order for dimension conversion. 
    so it has:  [most_significant_dim, ..., least_significant_dim]
    assume: 

        the size of i-th dimension to be:  S[i]
        the index of j-th dimension is: I[j]

    linear_idx of a n dimensional coordinate is: 

        I[n-1] * (S[n-2] * S[n-3] * S[n-4] *     ....    S[0]) +
        I[n-2] * (         S[n-3] * S[n-4] *     ....    S[0]) +       
        I[n-3] * (                  S[n-4] *     ....    S[0]) +  
        ...
        I[1]   * (                                       S[0]) + 
        I[0]

    """
    # NOTE the following function work based on a strong an assumption
    # that the processes in mesh are
    #    1. starts from 0
    #    2. continuous
    # it will be wrong if ths above condition doesnot meet,
    # e.g. process_mesh = { process_groups = [7, 8, 9,10, 12, 13, 14, 15], mesh = [2, 4]}
    # if you want a more general mapping, you should use cartesian product

    assert len(mesh_shape) == len(
        coordinate
    ), "coordinate should have the same size as mesh shape, but got shape: {}, coordinate: {}".format(
        mesh_shape, coordinate)
    for i in range(len(mesh_shape)):
        assert coordinate[
            i] >= 0, "index in dimension [{}] is least than zero. coordinate: {}".format(
                i, coordinate)
        assert coordinate[i] < mesh_shape[
            i], "index beyond extent in dimension [{}]. shape: {}, coordinate: {}".format(
                i, mesh_shape, coordinate)

    base = mesh_shape[-1]
    linear_idx = coordinate[-1]

    # row major order
    for i in range(len(mesh_shape) - 2, -1, -1):
        linear_idx += base * coordinate[i]
        base *= mesh_shape[i]

    return linear_idx


def _linear_idx2coordinate(mesh_shape, linear_idx):
    """
    mapping a linear scala into multidimensional mesh space, return it coordinate in that space.

    it is the inverse function of _coordinate2linear_idx.
    assume: 

        the size of i-th dimension to be:  S[i]
        the index of j-th dimension is: I[j]

    the coordinate given linear_idx is:

        I[0] = linear_idx                                  % S[0]
        I[0] = (linear_idx / S[0])                         % S[1]
        I[0] = (linear_idx / (S[0] * S[1]))                % S[2]
        ....

    """

    assert linear_idx >= 0, "linear index [{}] is least than zero".format(
        linear_idx)
    assert linear_idx < np.prod(
        mesh_shape
    ), "linear index beyond the extent of mesh shape. shape: {}, linear index: {}".format(
        mesh_shape, linear_idx)

    base = 1
    coordinate = [-1] * len(mesh_shape)

    for i in reversed(range(len(mesh_shape))):
        offset = linear_idx / base
        coordinate[i] = int(offset % mesh_shape[i])
        base *= mesh_shape[i]

    # row major order
    return coordinate


def _get_corresponding_rank(dist_context, target_mesh, rank):

    # TODO(JZ-LIANG) a hack method to support varying mesh in Pipeline parallelism case.
    # we assume that all mesh are evenly divide from a parent mesh and should have same size.
    # to revise this in future.

    coordinate = None
    for mesh in dist_context.process_meshes:
        if rank in mesh.processes and mesh.topology == target_mesh.topology:
            coordinate = _linear_idx2coordinate(mesh.topology,
                                                mesh.processes.index(rank))
            break

    assert coordinate is not None, "could NOT found rank [{}] in any registered mesh".format(
        rank)
    return target_mesh.processes[_coordinate2linear_idx(mesh.topology,
                                                        coordinate)]


def _get_unshard_dist_shape(var, dist_attr):
    var_shape = var.shape
    mapping = dist_attr.dims_mapping
    mesh = dist_attr.process_mesh.topology
    assert len(var_shape) == len(
        mapping
    ), "variable shape [{}] and dim_mapping [{}] is NOT match !".format(
        var_shape, mapping)
    new_shape = []
    for idx in range(len(var_shape)):
        if var_shape[idx] == -1 or mapping[idx] == -1:
            new_shape.append(var_shape[idx])
        else:
            new_shape.append(var_shape[idx] * mesh[mapping[idx]])

    return new_shape


def make_data_unshard(dist_main_prog, dist_startup_prog, dist_context=None):
    from .dist_context import get_default_distributed_context
    if dist_context is None:
        dist_context = get_default_distributed_context()

    for var in dist_main_prog.list_vars():
        if var.is_data:
            tensor_dist_attr = dist_context.get_tensor_dist_attr_for_program(
                var)
            inverse_shape = _get_unshard_dist_shape(var, tensor_dist_attr)
            var.desc.set_shape(inverse_shape)
            dim_mapping = tensor_dist_attr.dims_mapping
            dim_mapping = [-1] * len(dim_mapping)
            tensor_dist_attr.dims_mapping = dim_mapping
            dist_context.set_tensor_dist_attr_for_program(var, tensor_dist_attr)


def _update_addition_info(addition_info):
    """ Update default addition_info with inputs """
    add_info = {"epoch": 0, "batch": 0, "batch_size": 0}
    if not addition_info:
        return add_info
    elif not isinstance(addition_info, dict):
        raise TypeError("The type of 'addition_info' should be 'dict', "
                        "but got '{}'.".format(str(type(addition_info))))
    else:
        for item, value in addition_info.items():
            if item not in ["epoch", "batch", "batch_size"]:
                raise ValueError(
                    "The key of 'addition_info' should be one of the "
                    "['epoch', 'batch', 'batch_size'], but got '{}'."
                    .format(str(item)))
            if not isinstance(value, int):
                raise ValueError(
                    "The value of 'addition_info' should be 'int', "
                    "but got '{}'.".format(str(type(value))))
            add_info[item] = value
        return add_info


def _check_valid_path(file_path):
    """ Validity check of input file path """
    if not file_path:
        return file_path
    elif isinstance(file_path, list):
        for file in file_path:
            if not isinstance(file, str):
                raise TypeError("The type of file path should be 'str', "
                                "but got '{}'.".format(str(type(file))))
            if not os.path.exists(file):
                raise ValueError("The file path '{}' does not exist."
                                 .format(file))
        return file_path
    else:
        raise TypeError("The type of file path should be 'list', "
                        "but got '{}'.".format(str(type(file_path))))


def _check_param_dict(param_dict):
    if not param_dict:
        raise ValueError("'param_dict' cannot be None.")
    elif not isinstance(param_dict, dict):
        raise TypeError("The type of 'param_dict' should be 'dict', "
                        "but got '{}'.".format(str(type(param_dict))))
    else:
        for name, value in param_dict.items():
            if not isinstance(name, str):
                raise TypeError(
                    "The type of key of 'param_dict' should be 'str', "
                    "but got '{}'.".format(str(type(name))))
            if not isinstance(value, paddle.fluid.LoDTensor):
                raise TypeError(
                    "The type of value of 'param_dict' should be 'LoDTensor', "
                    "but got '{}'.".format(str(type(value))))
        return param_dict


def _check_dist_attr(dist_attr):
    if not dist_attr:
        return dist_attr
    elif not isinstance(dist_attr, dict):
        raise TypeError("The type of 'dist_attr' should be 'dict', "
                        "but got '{}'.".format(str(type(dist_attr))))
    else:
        for name, value in dist_attr.items():
            if not isinstance(name, str):
                raise TypeError(
                    "The type of param name of 'dist_attr' should be 'str', "
                    "but got '{}'.".format(str(type(name))))
            if not isinstance(value, dict):
                raise TypeError(
                    "The type of distributed attribute should be 'dict', "
                    "but got '{}'".format(str(type(value))))
            attr = ['process_shape', 'process_group', 'dims_mapping']
            if list(value.keys()) != attr:
                raise ValueError(
                    "The key of distributed attribute should be "
                    "'['process_shape', 'process_group', 'dims_mapping']', "
                    "but got {}.".format(str(value.keys())))
        return dist_attr


def save_distributed_checkpoint(program,
                                checkpoint_path,
                                dist_attr_path,
                                addition_info=None,
                                is_integrated=False,
                                dist_context=None):
    """ 
    Save model parameter state, optimzer state, distributed attribute and 
    additional information of each rank.

    Args:
        program(Program): The program to be saved.
        checkpoint_path(str): The path of the checkpoint file to be saved.
        dist_attr_path(str): The path of distributed attribute file to be saved.
        addition_info(dict, optional): Additional information, key should be selected in ['epoch', 'batch', 'batch_size'].
            Default values are 0, when 'addition_info' is None. Default: None.
        is_integrated(bool, optional): Whether to integrate param before save. Default: False.
        dist_context(DistributedContext ,optional): collect related distributed information for program

    Returns:
        None

    Examples:
        .. code-block:: python

            path = os.path.join("./output", "step_%d" % step)
            os.makedirs(path, exist_ok=True)
            add_info = {'batch': step, "batch_size": global_batch_size}
            save_distributed_checkpoint(program, path, path, add_info)
    """
    from .dist_context import get_default_distributed_context

    assert isinstance(program, paddle.fluid.framework.Program)
    assert isinstance(is_integrated, bool)
    if dist_context is None:
        dist_context = get_default_distributed_context()
    addition_info = _update_addition_info(addition_info)

    if not is_integrated:
        _save_distributed_state_dict(program, addition_info, checkpoint_path)
        _save_distributed_attribute(program, dist_attr_path, dist_context)
    else:
        # TODO: integrate param before save
        raise NotImplementedError(
            "Integrating parameter has not been implemented.")


def load_distributed_checkpoint(checkpoint_path, dist_attr_path):
    """ 
    Load parameter, optimizer, distributed attribute and addition_info.

    Args:
        checkpoint_path(list[str]): model parameter file path, must be in order of rank id.
        dist_attr_path(list[str]): distributed attribute file path, must be in order of rank id.

    Returns:
        param_dict(dict): parameters' value of all ranks.
        dist_attr(dict): parameters' distributed attribute.
        addition_info(dict): additional information user saved in last training. 

    Notes:
        The return, 'addition_info', is belonging to the first file of checkpoint_path by default.

    Examples:
        .. code-block:: python

            ckpt_path = ['./model_state_rank0.pdmodel', 
                         './model_state_rank1.pdmodel']
            dist_attr_path = ['./dist_attr_rank0.pdattr', 
                              './dist_attr_rank1.pdattr']
            param_dict, dist_attr, add_info = load_distributed_checkpoint(ckpt_path, dist_attr_path)
    """
    assert _check_valid_path(checkpoint_path), \
        "'checkpoint_path' cannot be None."
    assert _check_valid_path(dist_attr_path), \
        "'dist_attr_path' cannot be None."

    state_dict_info = _load_distributed_state_dict(checkpoint_path)
    dist_attr = _load_distributed_attribute(dist_attr_path)
    param_dict = state_dict_info["model"]
    addition_info = state_dict_info["addition_info"]
    return param_dict, dist_attr, addition_info


def load_checkpoint_into_program(checkpoint_path,
                                 dist_attr_path,
                                 program,
                                 dist_context=None):
    """ 
    Load parameter, optimizer, distributed attribute and addition_info into model.

    Args:
        checkpoint_path(list[str]): model parameter file path, must be in order of rank id.
        dist_attr_path(list[str]): distributed attribute file path, must be in order of rank id.
        program(Program): the program to be updated with checkpoint_path.
        dist_context(DistributedContext ,optional): collect related distributed information for program

    Returns:
        addition_info(dict): user saved in last train.
    
    Notes:
        The return, 'addition_info', is belonging to the first file of checkpoint_path by default.

    Examples:
        .. code-block:: python

            exe.run(startup_program)
            ckpt_path = ['./model_state_rank0.pdmodel', 
                         './model_state_rank1.pdmodel']
            dist_attr_path = ['./dist_attr_rank0.pdattr', 
                              './dist_attr_rank1.pdattr']
            load_checkpoint_into_program(ckpt_path, dist_attr_path, main_program)
    """
    from .dist_context import get_default_distributed_context

    assert isinstance(program, paddle.fluid.framework.Program)
    assert _check_valid_path(checkpoint_path), \
        "'checkpoint_path' cannot be None."
    assert _check_valid_path(dist_attr_path), \
        "'dist_attr_path' cannot be None."
    if dist_context is None:
        dist_context = get_default_distributed_context()
    all_state_dict_info = _load_distributed_state_dict(checkpoint_path)
    all_pre_dist_attr = _load_distributed_attribute(dist_attr_path)
    all_cur_dist_attr = get_dist_attr(program, dist_context)
    all_param_dict = all_state_dict_info["model"]
    addition_info = all_state_dict_info["addition_info"]
    sliced_param_dict = merge_and_slice_parameter(
        all_param_dict, all_pre_dist_attr, all_cur_dist_attr)
    load_parameter_into_program(sliced_param_dict, program)

    return addition_info


def load_parameter_into_program(param_dict, program):
    """ 
    Load parameters into program.

    Args:
        param_dict(dict): parameters' name and value.
        program(Program): the program to be updated
    """
    _check_param_dict(param_dict)
    assert program and isinstance(program, paddle.fluid.framework.Program)
    program.set_state_dict(param_dict)


def _save_distributed_attribute(program, dist_attr_path, dist_context):
    """ Save distributed attribute of all parameters """
    # TODO: just save a complete distributed attribute file
    rank_id = paddle.distributed.get_rank()
    dist_attr_name = os.path.join(dist_attr_path,
                                  "dist_attr_rank{}.pdattr".format(rank_id))
    dist_attr_dict = {
        "model": get_dist_attr(program, dist_context),
        "world_size": paddle.distributed.get_world_size()
    }
    paddle.save(dist_attr_dict, dist_attr_name)
    logging.info("Already saved distributed attribute to '{}'.".format(
        dist_attr_path))


def _load_distributed_attribute(dist_attr_path):
    """ Load parameters' distributed attribute from dist_attr_path """
    total_dist_attr = {}
    for dist_attr_file in dist_attr_path:
        dist_attr = paddle.load(dist_attr_file)
        pre_world_size = dist_attr["world_size"]
        assert pre_world_size == len(dist_attr_path), \
            "The number of 'dist_attr_path' must be equal to the last training world size."
        for name, attr in dist_attr["model"].items():
            if name not in total_dist_attr:
                total_dist_attr[name] = attr

    return total_dist_attr


def _save_distributed_state_dict(program, addition_info, checkpoint_path):
    """ Save parameters' state_dict """
    rank = paddle.distributed.get_rank()
    ckpt_file_name = os.path.join(checkpoint_path,
                                  "model_state_rank{}.pdmodel".format(rank))
    state_dict = {
        "model": program.state_dict(),
        "world_size": paddle.distributed.get_world_size(),
        "addition_info": addition_info
    }
    paddle.save(state_dict, ckpt_file_name)
    logging.info("Already saved model to '{}'.".format(checkpoint_path))


def _load_distributed_state_dict(checkpoint_path):
    """ Load parameters' state_dict from checkpoint_path """
    all_state_dict = {}
    for idx, ckpt_file in enumerate(checkpoint_path):
        state_dict_info = paddle.load(ckpt_file, return_numpy=True)
        pre_world_size = state_dict_info["world_size"]
        assert pre_world_size == len(checkpoint_path), \
            "The number of 'checkpoint_path' must be equal to the last training world size."
        if idx == 0:
            addition_info = state_dict_info["addition_info"]
        for name, value in state_dict_info["model"].items():
            if name in all_state_dict:
                all_state_dict[name].append(np.array(value))
            else:
                all_state_dict[name] = [np.array(value)]

    all_state_dict_info = {
        "model": all_state_dict,
        "addition_info": addition_info
    }
    return all_state_dict_info


def get_dist_attr(program, dist_context=None):
    """ 
    Get distributed attribute of current rank.

    Args:
        program(Program): main program for training
    """
    from .dist_context import get_default_distributed_context

    assert isinstance(program, paddle.fluid.framework.Program)
    if dist_context is None:
        dist_context = get_default_distributed_context()
    dist_attr = {}
    for var in program.list_vars():
        if is_parameter(var) or is_belong_to_optimizer(var):
            tensor_dist_attr = dist_context.get_tensor_dist_attr_for_program(
                var)
            process_mesh = tensor_dist_attr.process_mesh
            dims_mapping = tensor_dist_attr.dims_mapping
            dist_attr[var.name] = {
                "process_shape": process_mesh.topology,
                "process_group": process_mesh.processes,
                "dims_mapping": dims_mapping
            }
    return dist_attr


def merge_and_slice_parameter(dist_param_dict, pre_dist_attr, cur_dist_attr):
    """
    Merge parameters with previous dist_attr and slice parameters with current dist_attr

    Arags:
        dist_param_dict(dict): parameters' value of all ranks.
        pre_dist_attr(dict): parameters' dist_attr of last training process.
        cur_dist_attr(dict): parameters' dist_attr of current training process.

    Returns:
        dist_param_dict(dict): parameters' value of current rank.
    """
    assert _check_dist_attr(pre_dist_attr), "'pre_dist_attr' cannot be None."
    assert _check_dist_attr(cur_dist_attr), "'pre_dist_attr' cannot be None."
    assert isinstance(dist_param_dict, dict), \
        "The type of 'dist_param_dict' should be 'dict', but got {}.".format(
            str(type(dist_param_dict)))
    for name, value in dist_param_dict.items():
        if not isinstance(name, str):
            raise TypeError("The key of 'dist_param_dict' is parameter's name, "
                            "and its type should be 'str', but got {}."
                            .format(str(type(name))))
        if not isinstance(value, list) or not all(
                isinstance(v, np.ndarray) for v in value):
            raise TypeError(
                "The value of 'dist_param_dict' is parameter's value of all ranks, "
                "and its type should be 'list(numpy.ndarray)'.")

    param_not_in_pre = []
    param_not_in_cur = []
    logging.info("Start to merge and slice parameters.")
    for var_name in cur_dist_attr.keys():
        if var_name not in pre_dist_attr:
            param_not_in_pre.append(var_name)
            continue

        pre_attr = pre_dist_attr[var_name]
        cur_attr = cur_dist_attr[var_name]
        if pre_attr == cur_attr:
            # skip merge and slice
            rank_id = paddle.distributed.get_rank()
            index = cur_attr["process_group"].index(rank_id)
            param = dist_param_dict[var_name][index]
            dist_param_dict[var_name] = _to_LodTensor(param)
            continue

        pre_param = dist_param_dict[var_name]
        pre_dims_mapping = pre_attr["dims_mapping"]
        cur_dims_mapping = cur_attr["dims_mapping"]
        if len(set(pre_dims_mapping)) > 1 or -1 not in pre_dims_mapping:
            complete_param = _merge_parameter_with_dist_attr(pre_param,
                                                             pre_attr)
            dist_param_dict[var_name] = complete_param
        else:
            complete_param = pre_param[0]
            dist_param_dict[var_name] = _to_LodTensor(complete_param)

        if len(set(cur_dims_mapping)) > 1 or -1 not in cur_dims_mapping:
            sliced_param = _slice_parameter_with_dist_attr(complete_param,
                                                           cur_attr)
            dist_param_dict[var_name] = sliced_param

    for var_name in pre_dist_attr:
        if var_name not in cur_dist_attr:
            param_not_in_cur.append(var_name)
            dist_param_dict.pop(var_name)

    if param_not_in_pre:
        warnings.warn("Parameters '{}' are not found in last training process."
                      .format(str(param_not_in_pre)))
    if param_not_in_cur:
        warnings.warn(
            "Parameters '{}' are not found in current training process."
            .format(str(param_not_in_cur)))

    return dist_param_dict


def _merge_parameter_with_dist_attr(param_list, dist_attr):
    """ Merge parameter with distributed attribute """
    from .reshard import _compute_complete_shape, _compute_partition_index

    dims_mapping = dist_attr["dims_mapping"]
    process_shape = dist_attr["process_shape"]
    process_group = dist_attr["process_group"]
    # get the complete shape of the parameter
    complete_shape = _compute_complete_shape(param_list[0].shape, process_shape,
                                             dims_mapping)
    # merge the parameter with dist_attr
    partition_param_list = []
    merged_partiton = []
    for process in process_group:
        partition_index = _compute_partition_index(
            process, complete_shape, dims_mapping, process_shape, process_group)
        index = process_group.index(process)
        if partition_index not in merged_partiton:
            merged_partiton.append(partition_index)
            _merge_parameter(partition_param_list, param_list[index],
                             partition_index, complete_shape)

    assert len(partition_param_list) == 1 or not partition_param_list, \
        "Fail to merge parameter"
    complete_param = _to_LodTensor(partition_param_list[0][0])
    return complete_param


def _slice_parameter_with_dist_attr(param, dist_attr):
    """ Slice parameter with distributed attribute """
    param = np.array(param) if isinstance(param,
                                          paddle.fluid.LoDTensor) else param
    dims_mapping = dist_attr["dims_mapping"]
    process_shape = dist_attr["process_shape"]
    process_group = dist_attr["process_group"]
    # slice the parameter with dist_attr
    partition_index_list = _get_split_indices(param.shape, dims_mapping,
                                              process_shape, process_group)
    sliced_param_list = _slice_parameter(param, partition_index_list,
                                         len(partition_index_list))
    # get the current parameter's index in sliced_param_list
    rank_id = paddle.distributed.get_rank()
    sliced_param_index = _get_sliced_param_index(
        rank_id, param.shape, dims_mapping, process_shape, process_group)
    sliced_param = _to_LodTensor(sliced_param_list[sliced_param_index])
    return sliced_param


def _merge_parameter(partition_param_list, param, partition_index,
                     complete_shape):
    """
    Merge partitial parameters to a complete one.

    Returns:
        None

    Examples:
        .. code-block:: python

            import numpy as np
            partition_param_list = [(np.array([[[1.11, 1.12]]]), [[0,1],[0,1],[0,2]])]
            param = np.array([[[1.13, 1.14]]])
            partition_index = [[0,1],[0,1],[2,4]]

            _merge_parameter(partition_param_list, param, partition_index)
            # partition_param_list: [(np.array([[[1.11, 1.12, 1.13, 1.14]]]), [[0,1],[0,1],[0,4]])]
    """
    from .reshard import _compute_concat_info

    if len(partition_param_list) == 1:
        is_complete_data = True
        for idx, item in enumerate(partition_param_list[0][1]):
            if item[0] != 0 or item[1] != complete_shape[idx]:
                is_complete_data = False
                break
        if is_complete_data:
            return

    if not partition_param_list:
        partition_param_list.append((param, partition_index))
    else:
        i = 0
        while i < len(partition_param_list):
            concat_axis, first_order, new_partition = _compute_concat_info(
                partition_param_list[i][1], partition_index)
            if concat_axis != -1:
                if first_order == 0:
                    new_param = np.concatenate(
                        (partition_param_list[i][0], param), axis=concat_axis)
                else:
                    new_param = np.concatenate(
                        (param, partition_param_list[i][0]), axis=concat_axis)

                partition_param_list.pop(i)
                _merge_parameter(partition_param_list, new_param, new_partition,
                                 complete_shape)
                break
            i += 1


def _slice_parameter(complete_param, partition_index_list, length):
    """
    Slice a complete parameter.

    Returns:
        sliced_param_list(list): sliced parameters with 'partition_index_list'

    Examples:
        .. code-block:: python

            import numpy as np
            complete_param = np.array([[[1.11, 1.12, 1.13, 1.14, 1.15, 1.16]]])
            rank = 2
            complete_shape = [1, 1, 6]
            dims_mapping = [-1, -1, 0]
            process_shape = [3]
            process_group = [0, 1, 2]

            sliced_param_list = _slice_parameter(complete_param, [[], [], [2, 4]], 3)
            # [array([[[1.11, 1.12]]]), array([[[1.13, 1.14]]]), array([[[1.15, 1.16]]])]
    """
    sliced_param_list = []
    axis = len(complete_param.shape) - length
    sliced_param = np.split(
        complete_param, partition_index_list[axis], axis=axis)
    if length == 1:
        return sliced_param
    for param in sliced_param:
        sliced_param_list.extend(
            _slice_parameter(param, partition_index_list, length - 1))
    return sliced_param_list


def _get_sliced_param_index(rank, complete_shape, dims_mapping, process_shape,
                            process_group):
    """
    Get sliced_param's index of current rank in all sliced parameters list.

    Returns:
        sliced_param_index(int): the index of sliced param in sliced_param_list

    Examples:
        .. code-block:: python

            import numpy as np
            complete_param = np.array([[[1.11, 1.12, 1.13, 1.14, 1.15, 1.16]]])
            rank = 2
            complete_shape = [1, 1, 6]
            dims_mapping = [-1, -1, 0]
            process_shape = [3]
            process_group = [0, 1, 2]

            slice_param = _slice_parameter(complete_param, [[], [], [2, 4]], 3)
            # slice_param: 
            # [array([[[1.11, 1.12]]]), array([[[1.13, 1.14]]]), array([[[1.15, 1.16]]])]

            index = _get_sliced_param_index(rank, complete_shape, dims_mapping
                                            process_shape, process_group)
            # index: 2
    """
    from .reshard import _compute_partition_index

    partition_index = _compute_partition_index(
        rank, complete_shape, dims_mapping, process_shape, process_group)
    sliced_param_index = 0
    for i, shape in enumerate(complete_shape):
        if dims_mapping[i] == -1:
            slice_shape = shape
        else:
            slice_shape = shape // process_shape[dims_mapping[i]]
        if shape == 1:
            index = 0
        else:
            index = (partition_index[i][0] + 1) // slice_shape
        sliced_param_index = sliced_param_index * (shape // slice_shape) + index
    return sliced_param_index


def _get_split_indices(complete_shape, dims_mapping, process_shape,
                       process_group):
    """
    Get split indices of every dimension.

    Returns:
        split_indices_list(list): the split indices of every dimension of the parameter

    Examples:
        .. code-block:: python

            import numpy as np
            complete_param = np.array([[[1.11, 1.12, 1.13, 1.14, 1.15, 1.16]]])
            complete_shape = [1, 1, 6]
            dims_mapping = [-1, -1, 0]
            process_shape = [3]
            process_group = [0, 1, 2]

            index = _get_split_indices(complete_shape, dims_mapping, process_shape, process_group)
            # index: [[], [], [2, 4]]
    """
    from .reshard import _compute_partition_index

    split_indices_list = []
    for process in process_group:
        partition_index = _compute_partition_index(
            process, complete_shape, dims_mapping, process_shape, process_group)
        if split_indices_list:
            for dim in range(len(partition_index)):
                split_indices_list[dim].extend(partition_index[dim])
        else:
            split_indices_list = partition_index
    split_indices_list = list(
        map(lambda x, y: list(set(x) - set([y]) - set([0])), split_indices_list,
            complete_shape))
    split_indices_list = [sorted(x) for x in split_indices_list]
    return split_indices_list


def set_grad_var_shape(program, dist_context):
    from .operators.common import infer_shape
    from paddle.distributed.fleet.meta_optimizers.common import OpRole

    block = program.global_block()
    vars = block.vars
    for op in block.ops:
        if op.type == "sum":
            continue
        if int(op.attr('op_role')) == int(OpRole.Backward):
            op_dist_attr = dist_context.get_op_dist_attr_for_program(op)
            assert op_dist_attr is not None

            for var_name in op.output_arg_names:
                assert "@GRAD" in var_name
                forward_var_name = var_name[:var_name.find("@GRAD")]
                if op.type == "c_allreduce_sum" or op.type == "c_identity" or op.type == "scale":
                    forward_var_name = op.input_arg_names[0]

                need_set_shape_list = [
                    "reshape2_grad", "softmax_with_cross_entropy_grad",
                    "transpose2_grad", "softmax_grad", "cross_entropy_grad2",
                    "dropout_grad", "unsqueeze2_grad"
                ]
                forward_list = [
                    "reshape2", "softmax_with_cross_entropy", "transpose2",
                    "softmax", "cross_entropy2", "dropout", "unsqueeze2"
                ]
                if op.type in need_set_shape_list:
                    for forward_op in block.ops:
                        assert int(forward_op.attr('op_role')) != int(
                            OpRole.Backward)
                        idx = need_set_shape_list.index(op.type)
                        forward_op_name = forward_list[idx]
                        if forward_op.type == forward_op_name and forward_var_name in forward_op.input_arg_names:
                            op_dist_attr = dist_context.get_op_dist_attr_for_program(
                                forward_op)
                            break

                forward_input_dist_attr = op_dist_attr.get_input_dist_attr(
                    forward_var_name)
                assert forward_input_dist_attr is not None, f"{forward_var_name}"
                forward_var = vars[forward_var_name]
                forward_var_dist_attr = dist_context.get_tensor_dist_attr_for_program(
                    forward_var)
                assert forward_var_dist_attr is not None
                grad_var = vars[var_name]
                ref_shape = infer_shape(block, forward_var,
                                        forward_var_dist_attr,
                                        forward_input_dist_attr)

                if list(grad_var.shape) != ref_shape:
                    grad_var.desc.set_shape(ref_shape)


def update_op_dims_mapping_by_default_dist_impl(dist_op):
    changed = False
    op_dist_attr = dist_op.dist_attr
    op_desc = dist_op.serial_op.desc
    # The following statement will be replaced by a more elegent way
    if op_desc.type() == "shape" or op_desc.type() == "slice":
        return False
    output_names = op_desc.output_names()
    xshape_arg_names = []
    if "XShape" in output_names:
        xshape_arg_names = op_desc.output("XShape")
    batch_dim_mappings = []
    for arg_name in op_desc.input_arg_names():
        serial_tensor = dist_op.get_serial_input(arg_name)
        if serial_tensor.is_parameter:
            continue
        dims_mapping = op_dist_attr.get_input_dims_mapping(arg_name)
        if len(dims_mapping) > 1:
            for idx, mapping in enumerate(dims_mapping[1:]):
                assert mapping == -1, \
                    "{} only the batch dimension (0-dim) can be sharded, but the dimension {} is sharded by {} part."\
                        .format(op_desc.type(), idx, mapping)
        batch_dim_mappings.append(dims_mapping[0])
    for arg_name in op_desc.output_arg_names():
        serial_tensor = dist_op.get_serial_output(arg_name)
        if serial_tensor.is_parameter:
            continue
        dims_mapping = op_dist_attr.get_output_dims_mapping(arg_name)
        if arg_name not in xshape_arg_names:
            if len(dims_mapping) > 1:
                for idx, mapping in enumerate(dims_mapping[1:]):
                    assert mapping == -1, \
                        "{} only the batch dimension (0-dim) can be sharded, but the dimension {} is sharded by {} part."\
                            .format(op_desc.type(), idx, mapping)
            batch_dim_mappings.append(dims_mapping[0])
        else:
            assert dims_mapping[0] == -1, \
                "{} only the batch dimension (1-dim) of XShape can be sharded, but the dimension 0 is sharded by {} part."\
                    .format(op_desc.type(), mapping)
            if len(dims_mapping) > 2:
                for idx, mapping in enumerate(dims_mapping[2:]):
                    assert mapping == -1, \
                        "{} only the batch dimension (1-dim) of XShape can be sharded, but the dimension {} is sharded by {} part."\
                            .format(op_desc.type(), idx, mapping)
            batch_dim_mappings.append(dims_mapping[1])

    compatible_dim_mapping = compute_compatible_dim_mapping(batch_dim_mappings)
    assert compatible_dim_mapping is not None, "There is no compatible dim mapping."
    for arg_name in op_desc.input_arg_names():
        serial_tensor = dist_op.get_serial_input(arg_name)
        if serial_tensor.is_parameter:
            continue
        dims_mapping = op_dist_attr.get_input_dims_mapping(arg_name)
        if compatible_dim_mapping != dims_mapping[0]:
            dims_mapping[0] = compatible_dim_mapping
            changed = True
    for arg_name in op_desc.output_arg_names():
        serial_tensor = dist_op.get_serial_output(arg_name)
        if serial_tensor.is_parameter:
            continue
        dims_mapping = op_dist_attr.get_output_dims_mapping(arg_name)
        if arg_name not in xshape_arg_names:
            if compatible_dim_mapping != dims_mapping[0]:
                dims_mapping[0] = compatible_dim_mapping
                changed = True
        else:
            if compatible_dim_mapping != dims_mapping[1]:
                dims_mapping[1] = compatible_dim_mapping
                changed = True

    return changed


def update_op_dims_mapping_by_elementwise_like_dist_impl(dist_op):
    changed = False
    op_dist_attr = dist_op.dist_attr
    op_desc = dist_op.serial_op.desc
    input_arg_names = op_desc.input_arg_names()
    input_dims_mapping_dict = {}
    input_dims_mapping_lens = {}
    max_dims_mapping_len = -1
    for arg_name in input_arg_names:
        dims_mapping = op_dist_attr.get_input_dims_mapping(arg_name)
        if max_dims_mapping_len < len(dims_mapping):
            max_dims_mapping_len = len(dims_mapping)
        input_dims_mapping_dict[arg_name] = dims_mapping
        input_dims_mapping_lens[arg_name] = len(dims_mapping)

    dims_mapping_list = []
    for arg_name in input_arg_names:
        if input_dims_mapping_lens[arg_name] < max_dims_mapping_len:
            new_dims_mapping = [-1 for _ in range(max_dims_mapping_len)]
            for i in range(input_dims_mapping_lens[arg_name]):
                new_idx = (max_dims_mapping_len -
                           input_dims_mapping_lens[arg_name]) + i
                new_dims_mapping[new_idx] = input_dims_mapping_dict[arg_name][i]
            dims_mapping_list.append(new_dims_mapping)
        else:
            dims_mapping_list.append(input_dims_mapping_dict[arg_name])
    output_arg_names = op_desc.output_arg_names()
    for arg_name in output_arg_names:
        dims_mapping = op_dist_attr.get_output_dims_mapping(arg_name)
        assert len(dims_mapping) == max_dims_mapping_len
        dims_mapping_list.append(dims_mapping)

    compatible_dims_mapping = compute_compatible_dims_mapping(dims_mapping_list)
    assert compatible_dims_mapping is not None, "There is no compatible dim mapping."

    for arg_name in input_arg_names:
        if input_dims_mapping_lens[arg_name] < max_dims_mapping_len:
            new_dims_mapping = [
                -1 for _ in range(input_dims_mapping_lens[arg_name])
            ]
            for i in range(input_dims_mapping_lens[arg_name]):
                new_idx = (max_dims_mapping_len -
                           input_dims_mapping_lens[arg_name]) + i
                new_dims_mapping[i] = compatible_dims_mapping[new_idx]
            if new_dims_mapping != input_dims_mapping_dict[arg_name]:
                op_dist_attr.set_input_dims_mapping(arg_name, new_dims_mapping)
                changed = True
        else:
            if compatible_dims_mapping != input_dims_mapping_dict[arg_name]:
                op_dist_attr.set_input_dims_mapping(arg_name,
                                                    compatible_dims_mapping)
                changed = True

    for arg_name in output_arg_names:
        dims_mapping = op_dist_attr.get_output_dims_mapping(arg_name)
        if compatible_dims_mapping != dims_mapping:
            op_dist_attr.set_output_dims_mapping(arg_name,
                                                 compatible_dims_mapping)
            changed = True

    return changed


def get_all_distributed_main_program(serial_program_info, dist_context):
    "Get all distributed main programs by dist_context."
    from .dist_context import DistributedOperatorContext
    cluster = serial_program_info.cluster
    all_dist_main_program = []
    ranks = paddle.distributed.get_world_size() if cluster is None else len(
        cluster.get_all_devices("GPU"))
    for rank_id in range(ranks):
        used_dist_context = copy.deepcopy(dist_context)
        used_dist_context._dist_op_context = DistributedOperatorContext()
        dist_main_program, dist_startup_program = get_specified_distributed_main_program(
            serial_program_info, used_dist_context, rank_id)
        all_dist_main_program.append(dist_main_program)

    return all_dist_main_program


def get_specified_distributed_main_program(serial_program_info, dist_context,
                                           rank_id):
    "Get distributed main program by the given dist_context and rank_id."
    from .partitioner import Partitioner
    from .reshard import reshard, HAS_SENT, HAS_RECV, HAS_ALLGATHER
    from .process_group import _g_process_group_map, ProcessGroup

    dist_strategy = paddle.distributed.fleet.DistributedStrategy()
    train_program = serial_program_info.train_program
    startup_program = serial_program_info.startup_program
    loss = serial_program_info.loss
    optimizer = serial_program_info.optimizer

    partitioner = Partitioner(dist_strategy, dist_context, rank_id)
    dist_main_program, dist_startup_program = partitioner.transpile_forward(
        train_program, startup_program)
    dist_params_grads = partitioner.apply_backward(
        loss, train_program, startup_program, dist_main_program,
        dist_startup_program)
    opt_ops = partitioner.apply_optimize(
        copy.deepcopy(optimizer), dist_params_grads, dist_main_program,
        dist_startup_program)
    set_grad_var_shape(dist_main_program, dist_context)
    make_data_unshard(dist_main_program, dist_startup_program, dist_context)
    reshard(dist_main_program, dist_startup_program, rank_id, dist_context)
    HAS_SENT.clear()
    HAS_RECV.clear()
    HAS_ALLGATHER.clear()

    _g_process_group_map.clear()
    _g_process_group_map[0] = ProcessGroup(0, [])
    return dist_main_program, dist_startup_program


class SerialProgramInfo:
    def __init__(self,
                 train_program,
                 satrtup_program,
                 loss,
                 optimizer,
                 cluster=None):
        self._train_program = train_program
        self._startup_program = satrtup_program
        self._loss = loss
        self._optimizer = optimizer
        self._cluster = cluster

    @property
    def train_program(self):
        return self._train_program

    @property
    def startup_program(self):
        return self._startup_program

    @property
    def loss(self):
        return self._loss

    @property
    def optimizer(self):
        return self._optimizer

    @property
    def cluster(self):
        return self._cluster


def get_standalone_cost_data(distributed_programs):
    def _compute_runtime(op_cost, op, vars):
        runtime = 0
        try:
            runtime = float(op_cost["op_time"])
        except:
            return runtime
        op_config = op_cost["config"]
        total_static_input_size = 0
        total_actual_input_size = 0
        parsed_info = op_config.split("\n")
        variable = "(Variable)"
        for info in parsed_info:
            variable = "(Variable)" if "(Variable)" in info else "(list<Variable>"
            if variable in info:
                arg_name_lower = info[:info.find(variable) - 1]
                shape_left_boundary = info.find("[")
                shape_right_boundary = info.find("]")
                assert shape_left_boundary > 0 and shape_right_boundary > 0 and shape_right_boundary > shape_left_boundary, "Get shape failed."
                shape = info[shape_left_boundary + 1:
                             shape_right_boundary].split(",")
                shape = list(map(lambda x: int(x.strip()), shape))
                dtype_factor = 1
                total_static_input_size += reduce(lambda x, y: x * y, shape)
                # print(arg_name_lower)
                if op.type == "c_embedding":
                    arg_name_lower = "w" if arg_name_lower == "weight" else "ids"
                for arg_name in op.input_names:
                    if arg_name.lower() == arg_name_lower:
                        for var_name in op.input(arg_name):
                            var = vars[var_name]
                            total_actual_input_size += reduce(
                                lambda x, y: x * y, var.shape)
                        break
        assert total_static_input_size > 0 and total_actual_input_size > 0, "Get input size failed."

        actual_runtime = total_actual_input_size / total_static_input_size * runtime
        return actual_runtime

    cost_model = paddle.cost_model.CostModel()
    cost_model.static_cost_data()
    DEFAULT_MULTIPLE = 2
    OP_NAME_MAPPING = {
        "c_embedding": "embedding",
        "matmul_v2": "matmul",
        "transpose2": "transpose",
        "reshape2": "reshape",
        "unsqueeze2": "unsqueeze",
        "reduce_sum": "sum",
        "elementwise_div": "divide"
    }

    standalone_cost_data = []
    not_enum_ops = ["create_py_reader", "create_double_buffer_reader", "read"]
    for distributed_program in distributed_programs:
        cost_data = {}
        vars = distributed_program.global_block().vars
        for op in distributed_program.global_block().ops:
            runtime = 0
            if op.type in not_enum_ops:
                cost_data[op.desc.id()] = runtime
                continue
            dtype = str(vars[op.input_arg_names[0]]
                        .dtype) if op.input_arg_names else "float32"
            if int(op.attr('op_role')) == int(OpRole.Backward):
                if "_grad" in op.type:
                    forward_op_name = op.type[:-5]
                    if forward_op_name in OP_NAME_MAPPING.keys():
                        forward_op_name = OP_NAME_MAPPING[forward_op_name]
                    op_cost = cost_model.get_static_op_time(
                        forward_op_name, forward=False, dtype=dtype)
                    if op_cost:
                        runtime = _compute_runtime(op_cost, op, vars)
                    else:
                        op_cost = cost_model.get_static_op_time(
                            forward_op_name, dtype=dtype)
                        if op_cost:
                            runtime = 2 * _compute_runtime(op_cost, op, vars)
            elif int(op.attr('op_role')) == int(OpRole.Forward):
                op_name = OP_NAME_MAPPING[
                    op.type] if op.type in OP_NAME_MAPPING.keys() else op.type
                op_cost = cost_model.get_static_op_time(op_name)
                if op_cost:
                    runtime = _compute_runtime(op_cost, op, vars)

            cost_data[op.desc.id()] = runtime

        standalone_cost_data.append(cost_data)

    return standalone_cost_data