Giuseppe Rossini | f01201a | 2019-11-06 14:57:49 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2019 ARM Limited. |
| 3 | * |
| 4 | * SPDX-License-Identifier: MIT |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | * of this software and associated documentation files (the "Software"), to |
| 8 | * deal in the Software without restriction, including without limitation the |
| 9 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| 10 | * sell copies of the Software, and to permit persons to whom the Software is |
| 11 | * furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in all |
| 14 | * copies or substantial portions of the Software. |
| 15 | * |
| 16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 19 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 22 | * SOFTWARE. |
| 23 | */ |
| 24 | |
| 25 | #include <algorithm> |
| 26 | #include <cassert> |
| 27 | #include <cstdint> |
| 28 | #include <cmath> |
| 29 | #include <limits> |
| 30 | |
| 31 | #include "qsymm8.hpp" |
| 32 | |
| 33 | namespace qsymm8 { |
| 34 | #if(__ANDROID__ || BARE_METAL) |
| 35 | template <typename T> T round(T val) { return ::round(val); } |
| 36 | template <typename T> T exp2(T val) { return ::exp2(val); } |
| 37 | template <typename T> T log2(T val) { return ::log2(val); } |
| 38 | #else /* (__ANDROID__ || BARE_METAL) */ |
| 39 | template <typename T> T round(T val) { return std::round(val); } |
| 40 | template <typename T> T exp2(T val) { return std::exp2(val); } |
| 41 | template <typename T> T log2(T val) { return std::log2(val); } |
| 42 | #endif /* (__ANDROID__ || BARE_METAL) */ |
| 43 | |
| 44 | // Symmetric quantization |
| 45 | int8_t QSymm8Params::quantize(float value) const |
| 46 | { |
| 47 | const float transformed = value / scale; |
| 48 | return static_cast<int8_t>(round(std::max(-128.0f, std::min(127.0f, transformed)))); |
| 49 | } |
| 50 | |
| 51 | float QSymm8Params::dequantize(const int8_t value) const |
| 52 | { |
| 53 | return scale * (static_cast<float>(value)); |
| 54 | } |
| 55 | |
| 56 | QSymm8RescaleParams QSymm8RescaleParams::make_rescale_params( |
| 57 | const QSymm8Params& weight_quant, |
| 58 | const QSymm8Params& input_quant, |
| 59 | const QSymm8Params& output_quant |
| 60 | ) |
| 61 | { |
| 62 | // Based on the gemmlowp approach: https://github.com/google/gemmlowp/blob/master/doc/quantization_example.cc |
| 63 | const float rescale = weight_quant.scale * input_quant.scale / output_quant.scale; |
| 64 | const float shiftf = round(log2(0.5f / rescale)); |
| 65 | const float multf = exp2(31.0f + shiftf)*rescale; |
| 66 | |
| 67 | int64_t shift = static_cast<int64_t>(shiftf); |
| 68 | int64_t mult = static_cast<int64_t>(multf); |
| 69 | |
| 70 | if (mult == (1ll << 31)) |
| 71 | { |
| 72 | mult /= 2; |
| 73 | shift--; |
| 74 | } |
| 75 | |
| 76 | assert(shift >= 0); |
| 77 | assert(mult <= std::numeric_limits<int32_t>::max()); |
| 78 | |
| 79 | return QSymm8RescaleParams( |
| 80 | static_cast<int32_t>(shift), |
| 81 | static_cast<int32_t>(mult), |
| 82 | rescale |
| 83 | ); |
| 84 | } |
| 85 | |
| 86 | QSymm8RescaleParams::QSymm8RescaleParams(int32_t shift, int32_t multi, float rescale) |
| 87 | : shift(shift), multiplier(multi), rescale(rescale) |
| 88 | { |
| 89 | } |
| 90 | |
| 91 | // Symmetric per-channel quantization |
| 92 | int8_t QSymm8PerChannelParams::quantize(float value, float scale) const |
| 93 | { |
| 94 | const float transformed = value / scale; |
| 95 | return static_cast<int8_t>(round(std::max(-128.0f, std::min(127.0f, transformed)))); |
| 96 | } |
| 97 | |
| 98 | float QSymm8PerChannelParams::dequantize(const int8_t value, float scale) const |
| 99 | { |
| 100 | return scale * (static_cast<float>(value)); |
| 101 | } |
| 102 | |
| 103 | QSymm8PerChannelRescaleParams QSymm8PerChannelRescaleParams::make_rescale_params( |
| 104 | const QSymm8PerChannelParams& weight_quant, |
| 105 | const QSymm8PerChannelParams& input_quant, |
| 106 | const QSymm8PerChannelParams& output_quant |
| 107 | ) |
| 108 | { |
| 109 | std::vector<int32_t> shifts; |
| 110 | std::vector<int32_t> mults; |
| 111 | std::vector<float> rescales; |
| 112 | |
| 113 | for(size_t s = 0; s< input_quant.scales.size(); s++) |
| 114 | { |
| 115 | // Based on the gemmlowp approach: https://github.com/google/gemmlowp/blob/master/doc/quantization_example.cc |
| 116 | const float rescale = weight_quant.scales[s] * input_quant.scales[s] / output_quant.scales[s]; |
| 117 | const float shiftf = round(log2(0.5f / rescale)); |
| 118 | const float multf = exp2(31.0f + shiftf)*rescale; |
| 119 | |
| 120 | int64_t shift = static_cast<int64_t>(shiftf); |
| 121 | int64_t mult = static_cast<int64_t>(multf); |
| 122 | |
| 123 | if (mult == (1ll << 31)) |
| 124 | { |
| 125 | mult /= 2; |
| 126 | shift--; |
| 127 | } |
| 128 | |
| 129 | assert(shift >= 0); |
| 130 | assert(mult <= std::numeric_limits<int32_t>::max()); |
| 131 | |
| 132 | shifts.push_back(static_cast<int32_t>(shift)); |
| 133 | mults.push_back(static_cast<int32_t>(mult)); |
| 134 | rescales.push_back(rescale); |
| 135 | } |
| 136 | |
| 137 | return QSymm8PerChannelRescaleParams(shifts, mults, rescales); |
| 138 | |
| 139 | } |
| 140 | |
| 141 | QSymm8PerChannelRescaleParams QSymm8PerChannelRescaleParams::make_rescale_params( |
| 142 | const QSymm8PerChannelParams& weight_quant, |
| 143 | const qasymm8::QAsymm8Params& input_quant, |
| 144 | const qasymm8::QAsymm8Params& output_quant |
| 145 | ) |
| 146 | { |
| 147 | std::vector<int32_t> shifts; |
| 148 | std::vector<int32_t> mults; |
| 149 | std::vector<float> rescales; |
| 150 | |
| 151 | for(size_t s = 0; s< weight_quant.scales.size(); s++) |
| 152 | { |
| 153 | // Based on the gemmlowp approach: https://github.com/google/gemmlowp/blob/master/doc/quantization_example.cc |
| 154 | const float rescale = weight_quant.scales[s] * input_quant.scale / output_quant.scale; |
| 155 | const float shiftf = round(log2(0.5f / rescale)); |
| 156 | const float multf = exp2(31.0f + shiftf)*rescale; |
| 157 | |
| 158 | int64_t shift = static_cast<int64_t>(shiftf); |
| 159 | int64_t mult = static_cast<int64_t>(multf); |
| 160 | |
| 161 | if (mult == (1ll << 31)) |
| 162 | { |
| 163 | mult /= 2; |
| 164 | shift--; |
| 165 | } |
| 166 | |
| 167 | assert(shift >= 0); |
| 168 | assert(mult <= std::numeric_limits<int32_t>::max()); |
| 169 | |
| 170 | shifts.push_back(static_cast<int32_t>(shift)); |
| 171 | mults.push_back(static_cast<int32_t>(mult)); |
| 172 | rescales.push_back(rescale); |
| 173 | } |
| 174 | |
| 175 | return QSymm8PerChannelRescaleParams(shifts, mults, rescales); |
| 176 | |
| 177 | } |
| 178 | |
| 179 | QSymm8PerChannelRescaleParams::QSymm8PerChannelRescaleParams(std::vector<int32_t>& shifts, std::vector<int32_t>& multipliers, std::vector<float>& rescales) |
| 180 | : shifts(shifts), multipliers(multipliers), rescales(rescales) |
| 181 | { |
| 182 | } |
| 183 | |
| 184 | |
| 185 | } // namespace qasymm8 |