Add NNUE evaluation

This patch ports the efficiently updatable neural network (NNUE) evaluation to Stockfish.

Both the NNUE and the classical evaluations are available, and can be used to
assign a value to a position that is later used in alpha-beta (PVS) search to find the
best move. The classical evaluation computes this value as a function of various chess
concepts, handcrafted by experts, tested and tuned using fishtest. The NNUE evaluation
computes this value with a neural network based on basic inputs. The network is optimized
and trained on the evalutions of millions of positions at moderate search depth.

The NNUE evaluation was first introduced in shogi, and ported to Stockfish afterward.
It can be evaluated efficiently on CPUs, and exploits the fact that only parts
of the neural network need to be updated after a typical chess move.
[The nodchip repository](https://github.com/nodchip/Stockfish) provides additional
tools to train and develop the NNUE networks.

This patch is the result of contributions of various authors, from various communities,
including: nodchip, ynasu87, yaneurao (initial port and NNUE authors), domschl, FireFather,
rqs, xXH4CKST3RXx, tttak, zz4032, joergoster, mstembera, nguyenpham, erbsenzaehler,
dorzechowski, and vondele.

This new evaluation needed various changes to fishtest and the corresponding infrastructure,
for which tomtor, ppigazzini, noobpwnftw, daylen, and vondele are gratefully acknowledged.

The first networks have been provided by gekkehenker and sergiovieri, with the latter
net (nn-97f742aaefcd.nnue) being the current default.

The evaluation function can be selected at run time with the `Use NNUE` (true/false) UCI option,
provided the `EvalFile` option points the the network file (depending on the GUI, with full path).

The performance of the NNUE evaluation relative to the classical evaluation depends somewhat on
the hardware, and is expected to improve quickly, but is currently on > 80 Elo on fishtest:

60000 @ 10+0.1 th 1
https://tests.stockfishchess.org/tests/view/5f28fe6ea5abc164f05e4c4c
ELO: 92.77 +-2.1 (95%) LOS: 100.0%
Total: 60000 W: 24193 L: 8543 D: 27264
Ptnml(0-2): 609, 3850, 9708, 10948, 4885

40000 @ 20+0.2 th 8
https://tests.stockfishchess.org/tests/view/5f290229a5abc164f05e4c58
ELO: 89.47 +-2.0 (95%) LOS: 100.0%
Total: 40000 W: 12756 L: 2677 D: 24567
Ptnml(0-2): 74, 1583, 8550, 7776, 2017

At the same time, the impact on the classical evaluation remains minimal, causing no significant
regression:

sprt @ 10+0.1 th 1
https://tests.stockfishchess.org/tests/view/5f2906a2a5abc164f05e4c5b
LLR: 2.94 (-2.94,2.94) {-6.00,-4.00}
Total: 34936 W: 6502 L: 6825 D: 21609
Ptnml(0-2): 571, 4082, 8434, 3861, 520

sprt @ 60+0.6 th 1
https://tests.stockfishchess.org/tests/view/5f2906cfa5abc164f05e4c5d
LLR: 2.93 (-2.94,2.94) {-6.00,-4.00}
Total: 10088 W: 1232 L: 1265 D: 7591
Ptnml(0-2): 49, 914, 3170, 843, 68

The needed networks can be found at https://tests.stockfishchess.org/nns
It is recommended to use the default one as indicated by the `EvalFile` UCI option.

Guidelines for testing new nets can be found at
https://github.com/glinscott/fishtest/wiki/Creating-my-first-test#nnue-net-tests

Integration has been discussed in various issues:
https://github.com/official-stockfish/Stockfish/issues/2823
https://github.com/official-stockfish/Stockfish/issues/2728

The integration branch will be closed after the merge:
https://github.com/official-stockfish/Stockfish/pull/2825
https://github.com/official-stockfish/Stockfish/tree/nnue-player-wip

closes https://github.com/official-stockfish/Stockfish/pull/2912

This will be an exciting time for computer chess, looking forward to seeing the evolution of
this approach.

Bench: 4746616
This commit is contained in:
nodchip
2020-08-05 17:11:15 +02:00
committed by Joost VandeVondele
parent 9587eeeb5e
commit 84f3e86790
59 changed files with 2474 additions and 245 deletions
+215
View File
@@ -0,0 +1,215 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// Definition of layer AffineTransform of NNUE evaluation function
#ifndef NNUE_LAYERS_AFFINE_TRANSFORM_H_INCLUDED
#define NNUE_LAYERS_AFFINE_TRANSFORM_H_INCLUDED
#include <iostream>
#include "../nnue_common.h"
namespace Eval::NNUE::Layers {
// Affine transformation layer
template <typename PreviousLayer, IndexType OutputDimensions>
class AffineTransform {
public:
// Input/output type
using InputType = typename PreviousLayer::OutputType;
using OutputType = std::int32_t;
static_assert(std::is_same<InputType, std::uint8_t>::value, "");
// Number of input/output dimensions
static constexpr IndexType kInputDimensions =
PreviousLayer::kOutputDimensions;
static constexpr IndexType kOutputDimensions = OutputDimensions;
static constexpr IndexType kPaddedInputDimensions =
CeilToMultiple<IndexType>(kInputDimensions, kMaxSimdWidth);
// Size of forward propagation buffer used in this layer
static constexpr std::size_t kSelfBufferSize =
CeilToMultiple(kOutputDimensions * sizeof(OutputType), kCacheLineSize);
// Size of the forward propagation buffer used from the input layer to this layer
static constexpr std::size_t kBufferSize =
PreviousLayer::kBufferSize + kSelfBufferSize;
// Hash value embedded in the evaluation file
static constexpr std::uint32_t GetHashValue() {
std::uint32_t hash_value = 0xCC03DAE4u;
hash_value += kOutputDimensions;
hash_value ^= PreviousLayer::GetHashValue() >> 1;
hash_value ^= PreviousLayer::GetHashValue() << 31;
return hash_value;
}
// Read network parameters
bool ReadParameters(std::istream& stream) {
if (!previous_layer_.ReadParameters(stream)) return false;
stream.read(reinterpret_cast<char*>(biases_),
kOutputDimensions * sizeof(BiasType));
stream.read(reinterpret_cast<char*>(weights_),
kOutputDimensions * kPaddedInputDimensions *
sizeof(WeightType));
return !stream.fail();
}
// Forward propagation
const OutputType* Propagate(
const TransformedFeatureType* transformed_features, char* buffer) const {
const auto input = previous_layer_.Propagate(
transformed_features, buffer + kSelfBufferSize);
const auto output = reinterpret_cast<OutputType*>(buffer);
#if defined(USE_AVX512)
constexpr IndexType kNumChunks = kPaddedInputDimensions / (kSimdWidth * 2);
const __m512i kOnes = _mm512_set1_epi16(1);
const auto input_vector = reinterpret_cast<const __m512i*>(input);
#elif defined(USE_AVX2)
constexpr IndexType kNumChunks = kPaddedInputDimensions / kSimdWidth;
const __m256i kOnes = _mm256_set1_epi16(1);
const auto input_vector = reinterpret_cast<const __m256i*>(input);
#elif defined(USE_SSSE3)
constexpr IndexType kNumChunks = kPaddedInputDimensions / kSimdWidth;
const __m128i kOnes = _mm_set1_epi16(1);
const auto input_vector = reinterpret_cast<const __m128i*>(input);
#elif defined(USE_NEON)
constexpr IndexType kNumChunks = kPaddedInputDimensions / kSimdWidth;
const auto input_vector = reinterpret_cast<const int8x8_t*>(input);
#endif
for (IndexType i = 0; i < kOutputDimensions; ++i) {
const IndexType offset = i * kPaddedInputDimensions;
#if defined(USE_AVX512)
__m512i sum = _mm512_setzero_si512();
const auto row = reinterpret_cast<const __m512i*>(&weights_[offset]);
for (IndexType j = 0; j < kNumChunks; ++j) {
#if defined(__MINGW32__) || defined(__MINGW64__)
__m512i product = _mm512_maddubs_epi16(_mm512_loadu_si512(&input_vector[j]), _mm512_load_si512(&row[j]));
#else
__m512i product = _mm512_maddubs_epi16(_mm512_load_si512(&input_vector[j]), _mm512_load_si512(&row[j]));
#endif
product = _mm512_madd_epi16(product, kOnes);
sum = _mm512_add_epi32(sum, product);
}
output[i] = _mm512_reduce_add_epi32(sum) + biases_[i];
// Note: Changing kMaxSimdWidth from 32 to 64 breaks loading existing networks.
// As a result kPaddedInputDimensions may not be an even multiple of 64(512bit)
// and we have to do one more 256bit chunk.
if (kPaddedInputDimensions != kNumChunks * kSimdWidth * 2)
{
const auto iv_256 = reinterpret_cast<const __m256i*>(input);
const auto row_256 = reinterpret_cast<const __m256i*>(&weights_[offset]);
int j = kNumChunks * 2;
#if defined(__MINGW32__) || defined(__MINGW64__) // See HACK comment below in AVX2.
__m256i sum256 = _mm256_maddubs_epi16(_mm256_loadu_si256(&iv_256[j]), _mm256_load_si256(&row_256[j]));
#else
__m256i sum256 = _mm256_maddubs_epi16(_mm256_load_si256(&iv_256[j]), _mm256_load_si256(&row_256[j]));
#endif
sum256 = _mm256_madd_epi16(sum256, _mm256_set1_epi16(1));
sum256 = _mm256_hadd_epi32(sum256, sum256);
sum256 = _mm256_hadd_epi32(sum256, sum256);
const __m128i lo = _mm256_extracti128_si256(sum256, 0);
const __m128i hi = _mm256_extracti128_si256(sum256, 1);
output[i] += _mm_cvtsi128_si32(lo) + _mm_cvtsi128_si32(hi);
}
#elif defined(USE_AVX2)
__m256i sum = _mm256_setzero_si256();
const auto row = reinterpret_cast<const __m256i*>(&weights_[offset]);
for (IndexType j = 0; j < kNumChunks; ++j) {
__m256i product = _mm256_maddubs_epi16(
#if defined(__MINGW32__) || defined(__MINGW64__)
// HACK: Use _mm256_loadu_si256() instead of _mm256_load_si256. Because the binary
// compiled with g++ in MSYS2 crashes here because the output memory is not aligned
// even though alignas is specified.
_mm256_loadu_si256
#else
_mm256_load_si256
#endif
(&input_vector[j]), _mm256_load_si256(&row[j]));
product = _mm256_madd_epi16(product, kOnes);
sum = _mm256_add_epi32(sum, product);
}
sum = _mm256_hadd_epi32(sum, sum);
sum = _mm256_hadd_epi32(sum, sum);
const __m128i lo = _mm256_extracti128_si256(sum, 0);
const __m128i hi = _mm256_extracti128_si256(sum, 1);
output[i] = _mm_cvtsi128_si32(lo) + _mm_cvtsi128_si32(hi) + biases_[i];
#elif defined(USE_SSSE3)
__m128i sum = _mm_cvtsi32_si128(biases_[i]);
const auto row = reinterpret_cast<const __m128i*>(&weights_[offset]);
for (IndexType j = 0; j < kNumChunks; ++j) {
__m128i product = _mm_maddubs_epi16(
_mm_load_si128(&input_vector[j]), _mm_load_si128(&row[j]));
product = _mm_madd_epi16(product, kOnes);
sum = _mm_add_epi32(sum, product);
}
sum = _mm_hadd_epi32(sum, sum);
sum = _mm_hadd_epi32(sum, sum);
output[i] = _mm_cvtsi128_si32(sum);
#elif defined(USE_NEON)
int32x4_t sum = {biases_[i]};
const auto row = reinterpret_cast<const int8x8_t*>(&weights_[offset]);
for (IndexType j = 0; j < kNumChunks; ++j) {
int16x8_t product = vmull_s8(input_vector[j * 2], row[j * 2]);
product = vmlal_s8(product, input_vector[j * 2 + 1], row[j * 2 + 1]);
sum = vpadalq_s16(sum, product);
}
output[i] = sum[0] + sum[1] + sum[2] + sum[3];
#else
OutputType sum = biases_[i];
for (IndexType j = 0; j < kInputDimensions; ++j) {
sum += weights_[offset + j] * input[j];
}
output[i] = sum;
#endif
}
return output;
}
private:
using BiasType = OutputType;
using WeightType = std::int8_t;
PreviousLayer previous_layer_;
alignas(kCacheLineSize) BiasType biases_[kOutputDimensions];
alignas(kCacheLineSize)
WeightType weights_[kOutputDimensions * kPaddedInputDimensions];
};
} // namespace Eval::NNUE::Layers
#endif // #ifndef NNUE_LAYERS_AFFINE_TRANSFORM_H_INCLUDED
+186
View File
@@ -0,0 +1,186 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// Definition of layer ClippedReLU of NNUE evaluation function
#ifndef NNUE_LAYERS_CLIPPED_RELU_H_INCLUDED
#define NNUE_LAYERS_CLIPPED_RELU_H_INCLUDED
#include "../nnue_common.h"
namespace Eval::NNUE::Layers {
// Clipped ReLU
template <typename PreviousLayer>
class ClippedReLU {
public:
// Input/output type
using InputType = typename PreviousLayer::OutputType;
using OutputType = std::uint8_t;
static_assert(std::is_same<InputType, std::int32_t>::value, "");
// Number of input/output dimensions
static constexpr IndexType kInputDimensions =
PreviousLayer::kOutputDimensions;
static constexpr IndexType kOutputDimensions = kInputDimensions;
// Size of forward propagation buffer used in this layer
static constexpr std::size_t kSelfBufferSize =
CeilToMultiple(kOutputDimensions * sizeof(OutputType), kCacheLineSize);
// Size of the forward propagation buffer used from the input layer to this layer
static constexpr std::size_t kBufferSize =
PreviousLayer::kBufferSize + kSelfBufferSize;
// Hash value embedded in the evaluation file
static constexpr std::uint32_t GetHashValue() {
std::uint32_t hash_value = 0x538D24C7u;
hash_value += PreviousLayer::GetHashValue();
return hash_value;
}
// Read network parameters
bool ReadParameters(std::istream& stream) {
return previous_layer_.ReadParameters(stream);
}
// Forward propagation
const OutputType* Propagate(
const TransformedFeatureType* transformed_features, char* buffer) const {
const auto input = previous_layer_.Propagate(
transformed_features, buffer + kSelfBufferSize);
const auto output = reinterpret_cast<OutputType*>(buffer);
#if defined(USE_AVX2)
constexpr IndexType kNumChunks = kInputDimensions / kSimdWidth;
const __m256i kZero = _mm256_setzero_si256();
const __m256i kOffsets = _mm256_set_epi32(7, 3, 6, 2, 5, 1, 4, 0);
const auto in = reinterpret_cast<const __m256i*>(input);
const auto out = reinterpret_cast<__m256i*>(output);
for (IndexType i = 0; i < kNumChunks; ++i) {
const __m256i words0 = _mm256_srai_epi16(_mm256_packs_epi32(
#if defined(__MINGW32__) || defined(__MINGW64__)
// HACK: Use _mm256_loadu_si256() instead of _mm256_load_si256. Because the binary
// compiled with g++ in MSYS2 crashes here because the output memory is not aligned
// even though alignas is specified.
_mm256_loadu_si256
#else
_mm256_load_si256
#endif
(&in[i * 4 + 0]),
#if defined(__MINGW32__) || defined(__MINGW64__)
_mm256_loadu_si256
#else
_mm256_load_si256
#endif
(&in[i * 4 + 1])), kWeightScaleBits);
const __m256i words1 = _mm256_srai_epi16(_mm256_packs_epi32(
#if defined(__MINGW32__) || defined(__MINGW64__)
_mm256_loadu_si256
#else
_mm256_load_si256
#endif
(&in[i * 4 + 2]),
#if defined(__MINGW32__) || defined(__MINGW64__)
_mm256_loadu_si256
#else
_mm256_load_si256
#endif
(&in[i * 4 + 3])), kWeightScaleBits);
#if defined(__MINGW32__) || defined(__MINGW64__)
_mm256_storeu_si256
#else
_mm256_store_si256
#endif
(&out[i], _mm256_permutevar8x32_epi32(_mm256_max_epi8(
_mm256_packs_epi16(words0, words1), kZero), kOffsets));
}
constexpr IndexType kStart = kNumChunks * kSimdWidth;
#elif defined(USE_SSSE3)
constexpr IndexType kNumChunks = kInputDimensions / kSimdWidth;
#ifdef USE_SSE41
const __m128i kZero = _mm_setzero_si128();
#else
const __m128i k0x80s = _mm_set1_epi8(-128);
#endif
const auto in = reinterpret_cast<const __m128i*>(input);
const auto out = reinterpret_cast<__m128i*>(output);
for (IndexType i = 0; i < kNumChunks; ++i) {
const __m128i words0 = _mm_srai_epi16(_mm_packs_epi32(
_mm_load_si128(&in[i * 4 + 0]),
_mm_load_si128(&in[i * 4 + 1])), kWeightScaleBits);
const __m128i words1 = _mm_srai_epi16(_mm_packs_epi32(
_mm_load_si128(&in[i * 4 + 2]),
_mm_load_si128(&in[i * 4 + 3])), kWeightScaleBits);
const __m128i packedbytes = _mm_packs_epi16(words0, words1);
_mm_store_si128(&out[i],
#ifdef USE_SSE41
_mm_max_epi8(packedbytes, kZero)
#else
_mm_subs_epi8(_mm_adds_epi8(packedbytes, k0x80s), k0x80s)
#endif
);
}
constexpr IndexType kStart = kNumChunks * kSimdWidth;
#elif defined(USE_NEON)
constexpr IndexType kNumChunks = kInputDimensions / (kSimdWidth / 2);
const int8x8_t kZero = {0};
const auto in = reinterpret_cast<const int32x4_t*>(input);
const auto out = reinterpret_cast<int8x8_t*>(output);
for (IndexType i = 0; i < kNumChunks; ++i) {
int16x8_t shifted;
const auto pack = reinterpret_cast<int16x4_t*>(&shifted);
pack[0] = vqshrn_n_s32(in[i * 2 + 0], kWeightScaleBits);
pack[1] = vqshrn_n_s32(in[i * 2 + 1], kWeightScaleBits);
out[i] = vmax_s8(vqmovn_s16(shifted), kZero);
}
constexpr IndexType kStart = kNumChunks * (kSimdWidth / 2);
#else
constexpr IndexType kStart = 0;
#endif
for (IndexType i = kStart; i < kInputDimensions; ++i) {
output[i] = static_cast<OutputType>(
std::max(0, std::min(127, input[i] >> kWeightScaleBits)));
}
return output;
}
private:
PreviousLayer previous_layer_;
};
} // namespace Eval::NNUE::Layers
#endif // NNUE_LAYERS_CLIPPED_RELU_H_INCLUDED
+68
View File
@@ -0,0 +1,68 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
// NNUE evaluation function layer InputSlice definition
#ifndef NNUE_LAYERS_INPUT_SLICE_H_INCLUDED
#define NNUE_LAYERS_INPUT_SLICE_H_INCLUDED
#include "../nnue_common.h"
namespace Eval::NNUE::Layers {
// Input layer
template <IndexType OutputDimensions, IndexType Offset = 0>
class InputSlice {
public:
// Need to maintain alignment
static_assert(Offset % kMaxSimdWidth == 0, "");
// Output type
using OutputType = TransformedFeatureType;
// Output dimensionality
static constexpr IndexType kOutputDimensions = OutputDimensions;
// Size of forward propagation buffer used from the input layer to this layer
static constexpr std::size_t kBufferSize = 0;
// Hash value embedded in the evaluation file
static constexpr std::uint32_t GetHashValue() {
std::uint32_t hash_value = 0xEC42E90Du;
hash_value ^= kOutputDimensions ^ (Offset << 10);
return hash_value;
}
// Read network parameters
bool ReadParameters(std::istream& /*stream*/) {
return true;
}
// Forward propagation
const OutputType* Propagate(
const TransformedFeatureType* transformed_features,
char* /*buffer*/) const {
return transformed_features + Offset;
}
private:
};
} // namespace Layers
#endif // #ifndef NNUE_LAYERS_INPUT_SLICE_H_INCLUDED