libstdc++-v3/testsuite/performance/26_numerics/complex_norm.cc

   1 // Copyright (C) 2003-2018 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18
  19 #include <complex>
  20 #include <testsuite_performance.h>
  21
  22 // based on libstdc++/5730, use --fast-math
  23 int main()
  24 {
  25   using namespace std;
  26   using namespace __gnu_test;
  27
  28   time_counter time;
  29   resource_counter resource;
  30   const int iterations = 2000;
  31
  32   typedef complex<double> complex_type;
  33   complex_type u[2048];
  34
  35   for (int i = 0; i < 2048; ++i)
  36     u[i] = 1.0;
  37
  38   start_counters(time, resource);
  39   for (int i = 0; i < iterations; ++i)
  40     {
  41       complex_type * p = u;
  42       for (int j = 0; j < 2048; ++j)
  43         {
  44           double u2 = norm(*p);
  45           double t = u2 * 0.1;
  46           *p *= complex_type(cos(t), sin(t));
  47           ++p;
  48         }
  49     }
  50   stop_counters(time, resource);
  51   report_performance(__FILE__, "norm", time, resource);
  52   clear_counters(time, resource);
  53
  54   start_counters(time, resource);
  55   for (int i = 0; i < iterations; ++i)
  56     {
  57       complex_type * p = u;
  58       for (int j = 0; j < 2048; ++j)
  59         {
  60           // Shouldn't be slower than the above.
  61           double ur = real(*p);
  62           double ui = imag(*p);
  63           double u2 = ur * ur + ui * ui;
  64           double t = u2 * 0.1;
  65           *p *= complex_type(cos(t), sin(t));
  66           ++p;
  67         }
  68     }
  69   stop_counters(time, resource);
  70   report_performance(__FILE__, "", time, resource);
  71
  72   return 0;
  73 }
  74