test/src/test_normalise.cpp

   1 /* Copyright_License {
   2
   3   XCSoar Glide Computer - http://www.xcsoar.org/
   4   Copyright (C) 2000-2013 The XCSoar Project
   5   A detailed list of copyright holders can be found in the file "AUTHORS".
   6
   7   This program is free software; you can redistribute it and/or
   8   modify it under the terms of the GNU General Public License
   9   as published by the Free Software Foundation; either version 2
  10   of the License, or (at your option) any later version.
  11
  12   This program is distributed in the hope that it will be useful,
  13   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15   GNU General Public License for more details.
  16
  17   You should have received a copy of the GNU General Public License
  18   along with this program; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  20 }
  21 */
  22 #include "Math/FastMath.h"
  23 #include "TestUtil.hpp"
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27
  28 static
  29 void test_normalise_err(const int x, const int y)
  30 {
  31   int x0=x;
  32   int y0=y;
  33   i_normalise(x0, y0);
  34   int mag0 = iround((fixed)sqrt(x0*x0+y0*y0));
  35   int error0 = abs((1<<NORMALISE_BITS)-mag0);
  36
  37   int x1=x;
  38   int y1=y;
  39   i_normalise_fast(x1, y1);
  40   int mag1 = ihypot(x1, y1);
  41   int error1 = abs((1<<NORMALISE_BITS)-mag1);
  42
  43   bool err_ok = error1<= error0+1;
  44   if (!err_ok) {
  45     printf("# %d %d %d %d %d %d %d %d %d %d\n",
  46            x, y, x0, y0, mag0, error0, x1, y1, mag1, error1);
  47   }
  48
  49   char label[80];
  50   sprintf(label,"fast integer normalise error x=%d y=%d", x, y);
  51   ok(err_ok, label, 0);
  52 }
  53
  54 int slow_norm3(const int k, const int x, const int y, const int z);
  55
  56 int slow_norm3(const int k, const int x, const int y, const int z) {
  57   const long mag = (long)x*x+(long)y*y+(long)x*x;
  58   return (1<<NORMALISE_BITS)*k/isqrt4(mag);
  59 }
  60
  61 #ifdef FIXED_MATH
  62
  63 static
  64 void
  65 test_fixed_err()
  66 {
  67   bool err_ok=true;
  68   for (fixed x=fixed(0.0001); x< fixed(100000.0); x*= fixed(1.5)) {
  69     fixed y0 = fixed(1)/sqrt(x);
  70     fixed y1 = rsqrt(x);
  71     fixed err = fabs(y1 / y0 - fixed(1));
  72     bool this_ok = err< fixed(0.0001);
  73     err_ok &= this_ok;
  74     if (!this_ok) {
  75       printf("%g %g %g %g\n", (double)x, (double)y0, (double)y1, (double)err);
  76     }
  77   }
  78   ok(err_ok, "fixed rsqrt error", 0);
  79 }
  80
  81 #endif
  82
  83 int main(int argc, char** argv) {
  84
  85 #ifdef FIXED_MATH
  86   plan_tests(5);
  87 #else
  88   plan_tests(4);
  89 #endif
  90
  91   test_normalise_err(100, 50);
  92   test_normalise_err(-100, 50);
  93   test_normalise_err(100, -50);
  94   test_normalise_err(-100, -50);
  95
  96 #ifdef FIXED_MATH
  97   test_fixed_err();
  98 #endif
  99
 100   return exit_status();
 101 }
 102