kspaceduel/mathroutines.cpp

   1 /*
   2     Copyright (C) 1998-2001 Andreas Zehender <az@azweb.de>
   3
   4     it under the terms of the GNU General Public License as published by
   5     the Free Software Foundation; either version 2 of the License, or
   6     (at your option) any later version.
   7
   8     This program 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, write to the Free Software
  15     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  16 */
  17
  18 #include "mathroutines.h"
  19
  20 #include "math.h"
  21
  22 double rectToAngle(double x,double y)
  23 {
  24    double phi=0;
  25    if(fabs(x)<1e-6)
  26    {
  27       if(y>0)
  28          phi=M_PI_2;
  29       else
  30          phi=-M_PI_2;
  31    }
  32    else
  33    {
  34       phi=atan(y/x);
  35       if(x<0)
  36          phi+=M_PI;
  37    }
  38    if(phi>M_PI)
  39       phi-=2*M_PI;
  40    return phi;
  41 }
  42
  43 double average(double phi1,double phi2)
  44 {
  45    return phi2+difference(phi1,phi2)/2.0;
  46 }
  47
  48 double difference(double phi1,double phi2)
  49 {
  50    double dif;
  51
  52    dif=phi1-phi2;
  53    while(dif>M_PI)
  54       dif-=2*M_PI;
  55    while(dif<-M_PI)
  56       dif+=2*M_PI;
  57
  58    return dif;
  59 }