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| 1 | +/* |
| 2 | + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 |
| 3 | + Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file) |
| 4 | +
|
| 5 | + Stockfish is free software: you can redistribute it and/or modify |
| 6 | + it under the terms of the GNU General Public License as published by |
| 7 | + the Free Software Foundation, either version 3 of the License, or |
| 8 | + (at your option) any later version. |
| 9 | +
|
| 10 | + Stockfish is distributed in the hope that it will be useful, |
| 11 | + but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | + GNU General Public License for more details. |
| 14 | +
|
| 15 | + You should have received a copy of the GNU General Public License |
| 16 | + along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | +*/ |
| 18 | + |
| 19 | +// Definition of layer ClippedReLU of NNUE evaluation function |
| 20 | + |
| 21 | +#ifndef NNUE_LAYERS_SQR_CLIPPED_RELU_H_INCLUDED |
| 22 | +#define NNUE_LAYERS_SQR_CLIPPED_RELU_H_INCLUDED |
| 23 | + |
| 24 | +#include "../nnue_common.h" |
| 25 | + |
| 26 | +namespace Stockfish::Eval::NNUE::Layers { |
| 27 | + |
| 28 | + // Clipped ReLU |
| 29 | + template <IndexType InDims> |
| 30 | + class SqrClippedReLU { |
| 31 | + public: |
| 32 | + // Input/output type |
| 33 | + using InputType = std::int32_t; |
| 34 | + using OutputType = std::uint8_t; |
| 35 | + |
| 36 | + // Number of input/output dimensions |
| 37 | + static constexpr IndexType InputDimensions = InDims; |
| 38 | + static constexpr IndexType OutputDimensions = InputDimensions; |
| 39 | + static constexpr IndexType PaddedOutputDimensions = |
| 40 | + ceil_to_multiple<IndexType>(OutputDimensions, 32); |
| 41 | + |
| 42 | + using OutputBuffer = OutputType[PaddedOutputDimensions]; |
| 43 | + |
| 44 | + // Hash value embedded in the evaluation file |
| 45 | + static constexpr std::uint32_t get_hash_value(std::uint32_t prevHash) { |
| 46 | + std::uint32_t hashValue = 0x538D24C7u; |
| 47 | + hashValue += prevHash; |
| 48 | + return hashValue; |
| 49 | + } |
| 50 | + |
| 51 | + // Read network parameters |
| 52 | + bool read_parameters(std::istream&) { |
| 53 | + return true; |
| 54 | + } |
| 55 | + |
| 56 | + // Write network parameters |
| 57 | + bool write_parameters(std::ostream&) const { |
| 58 | + return true; |
| 59 | + } |
| 60 | + |
| 61 | + // Forward propagation |
| 62 | + const OutputType* propagate( |
| 63 | + const InputType* input, OutputType* output) const { |
| 64 | + |
| 65 | + #if defined(USE_SSE2) |
| 66 | + constexpr IndexType NumChunks = InputDimensions / 16; |
| 67 | + |
| 68 | + #ifdef USE_SSE41 |
| 69 | + const __m128i Zero = _mm_setzero_si128(); |
| 70 | + #else |
| 71 | + const __m128i k0x80s = _mm_set1_epi8(-128); |
| 72 | + #endif |
| 73 | + |
| 74 | + static_assert(WeightScaleBits == 6); |
| 75 | + const auto in = reinterpret_cast<const __m128i*>(input); |
| 76 | + const auto out = reinterpret_cast<__m128i*>(output); |
| 77 | + for (IndexType i = 0; i < NumChunks; ++i) { |
| 78 | + __m128i words0 = _mm_packs_epi32( |
| 79 | + _mm_load_si128(&in[i * 4 + 0]), |
| 80 | + _mm_load_si128(&in[i * 4 + 1])); |
| 81 | + __m128i words1 = _mm_packs_epi32( |
| 82 | + _mm_load_si128(&in[i * 4 + 2]), |
| 83 | + _mm_load_si128(&in[i * 4 + 3])); |
| 84 | + |
| 85 | + // Not sure if |
| 86 | + words0 = _mm_srli_epi16(_mm_mulhi_epi16(words0, words0), 3); |
| 87 | + words1 = _mm_srli_epi16(_mm_mulhi_epi16(words1, words1), 3); |
| 88 | + |
| 89 | + const __m128i packedbytes = _mm_packs_epi16(words0, words1); |
| 90 | + |
| 91 | + _mm_store_si128(&out[i], |
| 92 | + |
| 93 | + #ifdef USE_SSE41 |
| 94 | + _mm_max_epi8(packedbytes, Zero) |
| 95 | + #else |
| 96 | + _mm_subs_epi8(_mm_adds_epi8(packedbytes, k0x80s), k0x80s) |
| 97 | + #endif |
| 98 | + |
| 99 | + ); |
| 100 | + } |
| 101 | + constexpr IndexType Start = NumChunks * 16; |
| 102 | + |
| 103 | + #else |
| 104 | + constexpr IndexType Start = 0; |
| 105 | + #endif |
| 106 | + |
| 107 | + for (IndexType i = Start; i < InputDimensions; ++i) { |
| 108 | + output[i] = static_cast<OutputType>( |
| 109 | + // realy should be /127 but we need to make it fast |
| 110 | + // needs to be accounted for in the trainer |
| 111 | + std::max(0ll, std::min(127ll, (((long long)input[i] * input[i]) >> (2 * WeightScaleBits)) / 128))); |
| 112 | + } |
| 113 | + |
| 114 | + return output; |
| 115 | + } |
| 116 | + }; |
| 117 | + |
| 118 | +} // namespace Stockfish::Eval::NNUE::Layers |
| 119 | + |
| 120 | +#endif // NNUE_LAYERS_SQR_CLIPPED_RELU_H_INCLUDED |
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