Method _sync_with_cpp

python/paddle/base/framework.py:4925–5010

Sync from the desc on the c++ end. This method is used to synchronize the c++ desc instance generated by backward.

(self)

        return op

    def _sync_with_cpp(self):
        """
        Sync from the desc on the c++ end. This method is used to synchronize
        the c++ desc instance generated by backward.
        """
        # sync variables from cpp
        for var in self.desc.all_vars():
            if not self.has_var(var.name()):
                is_stop_gradient = False
                if var.has_stop_gradient():
                    is_stop_gradient = var.stop_gradient()
                if var.has_is_parameter() and var.is_parameter():
                    self.create_parameter(
                        name=var.name(),
                        desc=var,
                        type=var.type(),
                        shape=var.shape(),
                        dtype=var.dtype(),
                        stop_gradient=is_stop_gradient,
                    )
                else:
                    self.create_var(
                        name=var.name(),
                        desc=var,
                        type=var.type(),
                        stop_gradient=is_stop_gradient,
                    )

        # sync variables removed from c++ end
        for var in list(self.vars.keys()):
            if not self.desc.find_var(var.encode()):
                self.vars.pop(var)

        # 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]