# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

# Copyright (c) 2023, NVIDIA CORPORATION. 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.
"""
transpose last 2 dimensions of the input
"""

import torch.nn as nn


class TransposeLast(nn.Module):
    def __init__(self, deconstruct_idx=None):
        super().__init__()
        self.deconstruct_idx = deconstruct_idx

    def forward(self, x):
        if self.deconstruct_idx is not None:
            x = x[self.deconstruct_idx]
        return x.transpose(-2, -1)
