src/time.cpp

   1 /* Copyright (C) 2007-2012 Vincent Ollivier
   2  *
   3  * Purple Haze is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 3 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * Purple Haze is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <cassert>
  18 #include <iostream>
  19
  20 #include "time.h"
  21
  22 void Time::start_thinking(const unsigned int ply)
  23 {
  24     // Reset variables
  25     start = std::clock();
  26     abort_search = false;
  27     polling.interval = 1000000;
  28     polling.previous = 0;
  29
  30     clock.moves = ((ply / 2) % level.moves) + 1; // Used by allocated()
  31
  32     // Compute ratio
  33     const int time_per_move = allocated();
  34     if (time_per_move < 4 * 4) {
  35         ratio = 4;
  36     } else if (time_per_move < 8 * 8) {
  37         ratio = 8;
  38     } else {
  39         ratio = 16;
  40     }
  41     if (clock.moves == level.moves) { // Last move
  42         ratio /= 2;
  43     }
  44
  45     /*
  46     std::cout << "# start_thinking(" << ply << ")" << std::endl;
  47     std::cout << "#\tlevel = {" << level.moves << ", " << level.time << "}" << std::endl;
  48     std::cout << "#\tclock = {" << clock.moves << ", " << clock.time << "}" << std::endl;
  49     std::cout << "#\tratio = " << ratio << std::endl;
  50     std::cout << "#\ttpm   = " << time_per_move << std::endl;
  51     */
  52 }
  53
  54 inline bool Time::is_out_of_time() const
  55 {
  56     return ratio * elapsed() > (ratio - 1) * allocated();
  57 }
  58
  59 bool Time::poll(const unsigned int node_count)
  60 {
  61     // Avoid wasting time by calling 'is_out_of_time()' too frequently
  62     if (node_count - polling.previous > polling.interval) {
  63         polling.previous = node_count;
  64         abort_search = abort_search || is_out_of_time();
  65     }
  66     return abort_search;
  67 }