source/use_case/asr/src/AsrClassifier.cc

/*
 * Copyright (c) 2021 Arm Limited. All rights reserved.
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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.
 */
#include "AsrClassifier.hpp"

#include "log_macros.h"
#include "TensorFlowLiteMicro.hpp"
#include "Wav2LetterModel.hpp"

namespace arm {
namespace app {

    template<typename T>
    bool AsrClassifier::GetTopResults(TfLiteTensor* tensor,
                                      std::vector<ClassificationResult>& vecResults,
                                      const std::vector <std::string>& labels, double scale, double zeroPoint)
    {
        const uint32_t nElems = tensor->dims->data[Wav2LetterModel::ms_outputRowsIdx];
        const uint32_t nLetters = tensor->dims->data[Wav2LetterModel::ms_outputColsIdx];

        if (nLetters != labels.size()) {
            printf("Output size doesn't match the labels' size\n");
            return false;
        }

        /* NOTE: tensor's size verification against labels should be
         *       checked by the calling/public function. */
        if (nLetters < 1) {
            return false;
        }

        /* Final results' container. */
        vecResults = std::vector<ClassificationResult>(nElems);

        T* tensorData = tflite::GetTensorData<T>(tensor);

        /* Get the top 1 results. */
        for (uint32_t i = 0, row = 0; i < nElems; ++i, row+=nLetters) {
            std::pair<T, uint32_t> top_1 = std::make_pair(tensorData[row + 0], 0);

            for (uint32_t j = 1; j < nLetters; ++j) {
                if (top_1.first < tensorData[row + j]) {
                    top_1.first = tensorData[row + j];
                    top_1.second = j;
                }
            }

            double score = static_cast<int> (top_1.first);
            vecResults[i].m_normalisedVal = scale * (score - zeroPoint);
            vecResults[i].m_label = labels[top_1.second];
            vecResults[i].m_labelIdx = top_1.second;
        }

        return true;
    }
    template bool AsrClassifier::GetTopResults<uint8_t>(TfLiteTensor* tensor,
                                                        std::vector<ClassificationResult>& vecResults,
                                                        const std::vector <std::string>& labels,
                                                        double scale, double zeroPoint);
    template bool AsrClassifier::GetTopResults<int8_t>(TfLiteTensor* tensor,
                                                       std::vector<ClassificationResult>& vecResults,
                                                       const std::vector <std::string>& labels,
                                                       double scale, double zeroPoint);

    bool AsrClassifier::GetClassificationResults(
            TfLiteTensor* outputTensor,
            std::vector<ClassificationResult>& vecResults,
            const std::vector <std::string>& labels, uint32_t topNCount, bool use_softmax)
    {
            UNUSED(use_softmax);
            vecResults.clear();

            constexpr int minTensorDims = static_cast<int>(
                (Wav2LetterModel::ms_outputRowsIdx > Wav2LetterModel::ms_outputColsIdx)?
                 Wav2LetterModel::ms_outputRowsIdx : Wav2LetterModel::ms_outputColsIdx);

            constexpr uint32_t outColsIdx = Wav2LetterModel::ms_outputColsIdx;

            /* Sanity checks. */
            if (outputTensor == nullptr) {
                printf_err("Output vector is null pointer.\n");
                return false;
            } else if (outputTensor->dims->size < minTensorDims) {
                printf_err("Output tensor expected to be %dD\n", minTensorDims);
                return false;
            } else if (static_cast<uint32_t>(outputTensor->dims->data[outColsIdx]) < topNCount) {
                printf_err("Output vectors are smaller than %" PRIu32 "\n", topNCount);
                return false;
            } else if (static_cast<uint32_t>(outputTensor->dims->data[outColsIdx]) != labels.size()) {
                printf("Output size doesn't match the labels' size\n");
                return false;
            }

            if (topNCount != 1) {
                warn("TopNCount value ignored in this implementation\n");
            }

            /* To return the floating point values, we need quantization parameters. */
            QuantParams quantParams = GetTensorQuantParams(outputTensor);

            bool resultState;

            switch (outputTensor->type) {
                case kTfLiteUInt8:
                    resultState = this->GetTopResults<uint8_t>(
                            outputTensor, vecResults,
                            labels, quantParams.scale,
                            quantParams.offset);
                    break;
                case kTfLiteInt8:
                    resultState = this->GetTopResults<int8_t>(
                            outputTensor, vecResults,
                            labels, quantParams.scale,
                            quantParams.offset);
                    break;
                default:
                    printf_err("Tensor type %s not supported by classifier\n",
                        TfLiteTypeGetName(outputTensor->type));
                    return false;
            }

            if (!resultState) {
                printf_err("Failed to get sorted set\n");
                return false;
            }

            return true;
    }

} /* namespace app */
} /* namespace arm */