Python bindings for Lc0 backend.

.gitignore

@@ -4,6 +4,7 @@
 .DS_Store
 .clangd/
 build/
+__pycache__/
 compile_commands.json
 CUDA_NN/
 lc0.xcodeproj/

meson.build

@@ -504,8 +504,9 @@ endif
 executable('lc0', 'src/main.cc',
   files, include_directories: includes, dependencies: deps, install: true)
 
-
-### Tests
+#############################################################################
+## Tests
+#############################################################################
 
 if get_option('gtest')
   gtest = dependency('gtest', fallback: ['gtest', 'gtest_dep'])
@@ -543,3 +544,25 @@ if get_option('gtest')
   ), args: '--gtest_output=xml:encoder.xml', timeout: 90)
 
 endif
+
+
+#############################################################################
+## Python bindings
+#############################################################################
+
+if get_option('python_bindings')
+  pymod = import('python')
+  python = pymod.find_installation('python3')
+  py_bindings_generator = find_program('scripts/gen_py_bindings.py')
+
+  gen_py_bindings = custom_target('backends', input:[], output:['backends.cc'],
+    command : [py_bindings_generator, '@OUTPUT0@'])
+
+  py_files = [ gen_py_bindings ]
+
+  cpython = dependency('python3')
+  python.extension_module('backends',
+    [py_files + files],
+    include_directories: [includes],
+    dependencies: [cpython] + deps)
+endif

meson_options.txt

@@ -127,3 +127,8 @@ option('nvcc_ccbin',
        type: 'string',
        value: '',
        description: 'Override C++ compiler used by cuda nvcc')
+
+option('python_bindings',
+       type: 'boolean',
+       value: false,
+       description: 'Build Python bindings for the python to bind.')

scripts/compile_proto.py

@@ -1,5 +1,30 @@
 #!/usr/bin/env python3
 
+#  This file is part of Leela Chess Zero.
+#  Copyright (C) 2020 The LCZero Authors
+#
+#  Leela Chess 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.
+#
+#  Leela Chess 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 Leela Chess.  If not, see <http://www.gnu.org/licenses/>.
+#
+#  Additional permission under GNU GPL version 3 section 7
+#
+#  If you modify this Program, or any covered work, by linking or
+#  combining it with NVIDIA Corporation's libraries from the NVIDIA CUDA
+#  Toolkit and the NVIDIA CUDA Deep Neural Network library (or a
+#  modified version of those libraries), containing parts covered by the
+#  terms of the respective license agreement, the licensors of this
+#  Program grant you additional permission to convey the resulting work.
+
 import argparse
 import os
 import re
@@ -289,6 +314,14 @@ def GenerateFunctions(self, w):
                         (cpp_type, name, name))
             w.Write("const std::vector<%s>& %s() const { return %s_; }" %
                     (cpp_type, name, name))
+            if self.type.IsMessage():
+                w.Write("const %s& %s(size_t idx) const { return %s_[idx]; }" %
+                        (cpp_type, name, name))
+            else:
+                w.Write("%s %s(size_t) const { return %s_[idx]; }" %
+                        (cpp_type, name, name))
+            w.Write("size_t %s_size() const { return %s_.size(); }" %
+                    (name, name))
         else:
             w.Write("bool has_%s() const { return has_%s_; }" % (name, name))
             if self.type.IsMessage():

scripts/gen_py_bindings.py

@@ -0,0 +1,122 @@
+#!/bin/env python3
+
+#  This file is part of Leela Chess Zero.
+#  Copyright (C) 2020 The LCZero Authors
+#
+#  Leela Chess 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.
+#
+#  Leela Chess 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 Leela Chess.  If not, see <http://www.gnu.org/licenses/>.
+#
+#  Additional permission under GNU GPL version 3 section 7
+#
+#  If you modify this Program, or any covered work, by linking or
+#  combining it with NVIDIA Corporation's libraries from the NVIDIA CUDA
+#  Toolkit and the NVIDIA CUDA Deep Neural Network library (or a
+#  modified version of those libraries), containing parts covered by the
+#  terms of the respective license agreement, the licensors of this
+#  Program grant you additional permission to convey the resulting work.
+
+import sys
+from pybind.writer import Writer
+from pybind import Module, Class
+from pybind.parameters import (StringParameter, ClassParameter,
+                               NumericParameter, ArgvObjects, IntegralArgv,
+                               ListOfStringsParameter)
+from pybind.retval import (StringViewRetVal, StringRetVal, ListOfStringsRetVal,
+                           NumericRetVal, ObjCopyRetval, ObjOwnerRetval,
+                           ObjTupleRetVal, IntegralTupleRetVal)
+from pybind.exceptions import CppException
+
+# Module
+mod = Module('backends')
+mod.AddInclude('python/weights.h')
+mod.AddInitialization('lczero::InitializeMagicBitboards();')
+ex = mod.AddException(
+    CppException('LczeroException', cpp_name='lczero::Exception'))
+
+# Weights class
+weights = mod.AddClass(Class('Weights', cpp_name='lczero::python::Weights'))
+weights.constructor.AddParameter(
+    StringParameter('filename', optional=True, can_be_none=True)).AddEx(ex)
+weights.AddMethod('filename').AddRetVal(StringViewRetVal())
+weights.AddMethod('license').AddRetVal(StringViewRetVal())
+weights.AddMethod('min_version').AddRetVal(StringRetVal())
+weights.AddMethod('input_format').AddRetVal(NumericRetVal('i'))
+weights.AddMethod('policy_format').AddRetVal(NumericRetVal('i'))
+weights.AddMethod('value_format').AddRetVal(NumericRetVal('i'))
+weights.AddMethod('moves_left_format').AddRetVal(NumericRetVal('i'))
+weights.AddMethod('blocks').AddRetVal(NumericRetVal('i'))
+weights.AddMethod('filters').AddRetVal(NumericRetVal('i'))
+
+# Input class
+input = mod.AddClass(Class('Input', cpp_name='lczero::python::Input'))
+input.AddMethod('set_mask').AddParameter(NumericParameter('plane'),
+                                         NumericParameter(
+                                             'mask', type='u64')).AddEx(ex)
+input.AddMethod('set_val').AddParameter(NumericParameter('plane'),
+                                        NumericParameter('value',
+                                                         type='f32')).AddEx(ex)
+input.AddMethod('mask').AddParameter(NumericParameter('plane')).AddRetVal(
+    NumericRetVal('u64')).AddEx(ex)
+input.AddMethod('val').AddParameter(NumericParameter('plane')).AddRetVal(
+    NumericRetVal('f32')).AddEx(ex)
+input.AddMethod('clone').AddRetVal(ObjOwnerRetval(input))
+
+# Output class
+output = mod.AddClass(
+    Class('Output',
+          cpp_name='lczero::python::Output',
+          disable_constructor=True))
+output.AddMethod('q').AddRetVal(NumericRetVal('f32'))
+output.AddMethod('d').AddRetVal(NumericRetVal('f32'))
+output.AddMethod('m').AddRetVal(NumericRetVal('f32'))
+output.AddMethod('p_raw').AddParameter(IntegralArgv('samples', 'i')).AddRetVal(
+    IntegralTupleRetVal('f32')).AddEx(ex)
+output.AddMethod('p_softmax').AddParameter(IntegralArgv(
+    'samples', 'i')).AddRetVal(IntegralTupleRetVal('f32')).AddEx(ex)
+
+# Backend capabilities class
+backend_caps = mod.AddClass(
+    Class('BackendCapabilities',
+          cpp_name='lczero::python::BackendCapabilities',
+          disable_constructor=True))
+backend_caps.AddMethod('input_format').AddRetVal(NumericRetVal('i'))
+backend_caps.AddMethod('moves_left_format').AddRetVal(NumericRetVal('i'))
+
+# Backend class
+backend = mod.AddClass(Class('Backend', cpp_name='lczero::python::Backend'))
+backend.AddStaticMethod('available_backends').AddRetVal(ListOfStringsRetVal())
+backend.constructor.AddParameter(
+    ClassParameter(weights, 'weights', optional=True),
+    StringParameter('backend', optional=True, can_be_none=True),
+    StringParameter('options', optional=True, can_be_none=True)).AddEx(ex)
+backend.AddMethod('evaluate').AddParameter(ArgvObjects(
+    'inputs', input)).AddRetVal(ObjTupleRetVal(output)).AddEx(ex)
+backend.AddMethod('capabilities').AddRetVal(ObjCopyRetval(backend_caps))
+
+# PositionHistory class
+game_state = mod.AddClass(
+    Class('GameState', cpp_name='lczero::python::GameState'))
+game_state.constructor.AddParameter(
+    StringParameter('fen', optional=True, can_be_none=True),
+    ListOfStringsParameter('moves', optional=True),
+).AddEx(ex)
+game_state.AddMethod('as_input').AddParameter(
+    ClassParameter(backend, 'backend',
+                   optional=False)).AddRetVal(ObjOwnerRetval(input)).AddEx(ex)
+game_state.AddMethod('moves').AddRetVal(ListOfStringsRetVal())
+game_state.AddMethod('policy_indices').AddRetVal(IntegralTupleRetVal('i'))
+game_state.AddMethod('as_string').AddRetVal(StringRetVal())
+
+with open(sys.argv[1], 'wt') as f:
+    writer = Writer(f)
+    mod.Generate(writer)