src/time.cpp

   1 /* Copyright (C) 2007-2011 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 <iostream>
  18
  19 #include "time.h"
  20 #include "assert.h"
  21
  22 void Time::start_thinking(const unsigned int ply)
  23 {
  24     // Reset variables
  25     start = clock();
  26     abort_search = false;
  27     polling.interval = 1000000;
  28     polling.previous = 0;
  29
  30     // Compute time per move
  31     if (remaining != time_per_move) {
  32         unsigned int n = level_moves;
  33         n = n - (((ply + 1) / 2) % n);
  34         assert(n > 0);
  35         time_per_move = remaining / n;
  36     } else {
  37         assert(level_moves > 0);
  38         time_per_move = level_time / level_moves;
  39     }
  40
  41     // Compute coefs
  42     if (time_per_move > 3000) {
  43         coef_1 = 16; coef_2 = 15;
  44     } else if (time_per_move > 1000) {
  45         coef_1 = 4; coef_2 = 3;
  46     } else {
  47         coef_1 = 5; coef_2 = 3;
  48     }
  49 }
  50
  51 bool Time::is_out_of_time() const
  52 {
  53     return coef_1 * elapsed() > coef_2 * allocated();
  54 }
  55
  56 bool Time::poll(const unsigned int node_count)
  57 {
  58     // Avoid wasting time by calling 'is_out_of_time()' too frequently
  59     if (node_count - polling.previous > polling.interval) {
  60         polling.previous = node_count;
  61         abort_search = is_out_of_time();
  62     }
  63     return abort_search;
  64 }