src/core/utils/ScaleUtils.cpp

/*
 * Copyright (c) 2020, 2022 Arm Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
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 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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#include "src/core/utils/ScaleUtils.h"
#include "src/common/cpuinfo/CpuIsaInfo.h"

#include "arm_compute/core/CPP/CPPTypes.h"
#include "arm_compute/core/TensorInfo.h"

float arm_compute::scale_utils::calculate_resize_ratio(size_t input_size, size_t output_size, bool align_corners)
{
    const size_t offset = (align_corners && output_size > 1) ? 1 : 0;
    const auto   in     = input_size - offset;
    const auto   out    = output_size - offset;

    ARM_COMPUTE_ERROR_ON((input_size == 0 || output_size == 0) && offset == 1);
    ARM_COMPUTE_ERROR_ON(out == 0);

    return static_cast<float>(in) / static_cast<float>(out);
}

bool arm_compute::scale_utils::is_precomputation_required(DataLayout data_layout, DataType data_type, InterpolationPolicy policy)
{
    // whether to precompute indices & weights
    // The Neon™ kernels (which are preferred over SVE when policy is BILINEAR) do not use
    // precomputed index and weights when data type is FP32/16.
    // If policy is nearest_neighbor for SVE, then precompute because it's being used
    // To be revised in COMPMID-5453/5454
    return data_layout != DataLayout::NHWC || (data_type != DataType::F32 && data_type != DataType::F16) || (CPUInfo::get().get_isa().sve == true && policy == InterpolationPolicy::NEAREST_NEIGHBOR);
}