Search Refactor & Verification

.travis.yml

@@ -1,15 +1,26 @@
 language: cpp
 compiler: gcc
-dist: trusty
+dist: xenial
+
 notifications:
   email: false
 
+addons:
+  apt:
+    sources:
+    - deadsnakes
+    packages:
+    - python3.7-dev
+
 before_install:
   # C++17
   - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
   - sudo apt-get update -qq
 
 install: 
+  - pyenv global $(pyenv whence 2to3)  # activate all python versions
+  - pip install pipenv
+
   # C++17
   - sudo apt-get install -qq g++-7 gcc-7
   - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-7 90
@@ -21,6 +32,15 @@ install:
   - tar xf lcov_1.11.orig.tar.gz
   - sudo make -C lcov-1.11/ install  
   - which lcov 
+
+  # Install stockfish (used in search verification). Script from https://github.com/niklasf/python-chess/blob/master/.travis.yml
+  - wget https://stockfish.s3.amazonaws.com/stockfish-10-linux.zip
+  - unzip stockfish-10-linux.zip
+  - mkdir -p bin
+  - cp stockfish-10-linux/Linux/stockfish_10_x64_modern bin/stockfish
+  - chmod +x bin/stockfish
+  - export PATH="`pwd`/bin:${PATH}"
+  - which stockfish || (echo $PATH && false)
 
   # Install coverals gem for uploading coverage to coveralls.
   - gem install coveralls-lcov
@@ -30,18 +50,17 @@ before_script:
   - gcov --version
   - g++ --version
   - PARENTDIR=$(pwd)
-  - mkdir $PARENTDIR/build && cd $PARENTDIR/build
 
 script:
+  - pipenv install
+  - CMAKE_BUILD_TYPE=Coverage pipenv run python tests/test_search.py
   - cd $PARENTDIR/build
-  - cmake -DCMAKE_BUILD_TYPE=Coverage $PARENTDIR
-  - make
-  - make gtest
+  - make bench  
   - make coverage
-  - printf "bench\nquit\n" | ./goldfish.x
 
 after_success:
   - cd $PARENTDIR/build
   - lcov --list coverage_out.info.cleaned  # Show test report in travis log.
   - coveralls-lcov coverage_out.info.cleaned  # uploads to coveralls
+  - bash <(curl -s https://codecov.io/bash) -f coverage_out.info.cleaned || echo "Codecov did not collect coverage reports"
 

CMakeLists.txt

@@ -10,7 +10,7 @@
 cmake_minimum_required(VERSION 3.0)
 
 # Set project name here.
-project(Goldfish VERSION 1.8.2 LANGUAGES CXX)
+project(Goldfish VERSION 1.9.0 LANGUAGES CXX)
 
 # Include stuff. No change needed.
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/")
@@ -31,7 +31,7 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wfatal-errors")
 
 # Build-type specific flags. Change as needed.
 SET(CMAKE_CXX_FLAGS_RELEASE "-O3 -DNDEBUG")
-SET(CMAKE_CXX_FLAGS_DEBUG "-g -Og")
+SET(CMAKE_CXX_FLAGS_DEBUG "-g -O0")
 
 message(STATUS "Building with the following extra flags: ${CMAKE_CXX_FLAGS}")
 
@@ -88,6 +88,9 @@ set(SOURCES
         src/perft.cpp
         src/position.cpp
         src/search.cpp
+        src/searchmanagement.cpp
+        src/semaphore.cpp
+        src/timer.cpp
         src/tt.cpp
         )
 set(TESTFILES

Pipfile

@@ -0,0 +1,13 @@
+[[source]]
+name = "pypi"
+url = "https://pypi.org/simple"
+verify_ssl = true
+
+[dev-packages]
+
+[packages]
+chester = "*"
+python-chess = "*"
+
+[requires]
+python_version = "3.7"

README.md

@@ -1,6 +1,7 @@
 [![Project Status: Active – The project has reached a stable, usable state and is being actively developed.](http://www.repostatus.org/badges/latest/active.svg)](http://www.repostatus.org/#active)
 [![Build Status](https://travis-ci.org/bsamseth/Goldfish.svg?branch=master)](https://travis-ci.org/bsamseth/Goldfish)
 [![Coverage Status](https://coveralls.io/repos/github/bsamseth/Goldfish/badge.svg?branch=master)](https://coveralls.io/github/bsamseth/Goldfish?branch=master)
+[![codecov](https://codecov.io/gh/bsamseth/Goldfish/branch/master/graph/badge.svg)](https://codecov.io/gh/bsamseth/Goldfish)
 [![Codacy Badge](https://api.codacy.com/project/badge/Grade/7f53976fd4bb42b4bfb2f53bd67fce65)](https://www.codacy.com/app/bsamseth/Goldfish?utm_source=github.com&utm_medium=referral&utm_content=bsamseth/Goldfish&utm_campaign=Badge_Grade)
 [![Language grade: C/C++](https://img.shields.io/lgtm/grade/cpp/g/bsamseth/Goldfish.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/bsamseth/Goldfish/context:cpp)
 [![Language grade: Python](https://img.shields.io/lgtm/grade/python/g/bsamseth/Goldfish.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/bsamseth/Goldfish/context:python)
@@ -59,7 +60,7 @@ been added so far. The list is inspired in large part by [this writeup](http://w
 -   [X] Killer move heuristic
 -   [X] Principal variation search
 -   [X] Internal iterative deepening
--   [X] Aspiration window search
+-   [X] Aspiration window search (repealed by PR #27, needs tuning before reapplying)
 -   [ ] Futility pruning
 -   [ ] Delta pruning in quiescence search.
     +   [X] Prune when _no_ move can improve enough

cmake/CodeCoverage.cmake

@@ -103,7 +103,7 @@ FUNCTION(SETUP_TARGET_FOR_COVERAGE _targetname _testrunner _outputname)
 	ADD_CUSTOM_TARGET(${_targetname}
 
 		# Cleanup lcov
-		${LCOV_PATH} --directory . --zerocounters
+		# ${LCOV_PATH} --directory . --zerocounters
 
 		# Run tests
 		COMMAND ${_testrunner} ${ARGV3}

include/bound.hpp

@@ -4,7 +4,7 @@
 
 namespace goldfish {
 
-enum class Bound : uint8_t {
+enum Bound : uint8_t {
     NONE, LOWER, UPPER, EXACT = LOWER | UPPER
 };
 

include/position.hpp

@@ -74,6 +74,8 @@ class Position {
 
     bool is_attacked(Square target_square, Color attacker_color);
 
+    bool last_move_was_null_move();
+
 private:
     class Zobrist {
     public:
@@ -109,6 +111,9 @@ class Position {
     std::array<State, MAX_MOVES> states;
     int states_size = 0;
 
+    std::array<Move, MAX_MOVES> moves;
+    int move_count = 0;
+
     Zobrist &zobrist;
 
     void clear_castling(Square square);

include/search.hpp

@@ -144,13 +144,27 @@ class Search {
 
     void update_search(int ply);
 
+    void save_pv(const Move move, const MoveVariation &src, MoveVariation &dest);
+
+    Value pv_search(Depth depth, Value alpha, Value beta, int ply, int move_number);
+
     Value search_root(Depth depth, Value alpha, Value beta);
 
     Value search(Depth depth, Value alpha, Value beta, int ply);
 
     Value quiescent(Value alpha, Value beta, int ply);
-
-    void save_pv(Move move, MoveVariation &src, MoveVariation &dest);
 };
 
+inline uint64_t Search::get_total_nodes() {
+    return total_nodes;
+}
+
+inline void Search::save_pv(const Move move, const MoveVariation &src, MoveVariation &dest) {
+    dest.moves[0] = move;
+    for (int i = 0; i < src.size; i++) {
+        dest.moves[i + 1] = src.moves[i];
+    }
+    dest.size = src.size + 1;
+}
+
 }

include/tt.hpp

@@ -60,4 +60,22 @@ void TranspositionTable<Mb_Size>::store(const uint64_t key, Value value, Bound b
     tte->save(key, value, bound, depth, move);
 }
 
+// value_to_tt() adjusts a mate score from "plies to mate from the root" to
+// "plies to mate from the current position". Non-mate scores are unchanged.
+// The function is called before storing a value in the transposition table.
+constexpr Value value_to_tt(Value v, int ply) {
+    assert(v != Value::NO_VALUE);
+    return  v >= Value::CHECKMATE_THRESHOLD ? v + ply
+        : v <= Value::CHECKMATE_THRESHOLD ? v - ply : v;
+}
+
+// value_from_tt() is the inverse of value_to_tt(): It adjusts a mate score
+// from the transposition table (which refers to the plies to mate/be mated
+// from current position) to "plies to mate/be mated from the root".
+constexpr Value value_from_tt(Value v, int ply) {
+    return  v == Value::NO_VALUE ? Value::NO_VALUE
+        : v >= Value::CHECKMATE_THRESHOLD ? v - ply
+        : v <= Value::CHECKMATE_THRESHOLD ? v + ply : v;
+}
+
 }