# Adapted from https://github.com/NVIDIA/NeMo/blob/r0.9/collections/nemo_asr/
# Copyright (C) 2020 Xilinx (Giuseppe Franco)
# Copyright (C) 2019 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.
import torch
import torch.nn as nn


class GreedyCTCDecoder(nn.Module):
    """
    Greedy decoder that computes the argmax over a softmax distribution
    """

    def __init__(self):
        nn.Module.__init__(self)

    def forward(self, log_probs):
        with torch.no_grad():
            argmx = log_probs.argmax(dim=-1, keepdim=False)
            return argmx
