vide_public/c_tools/hod/complex.c

125 lines
2 KiB
C

/* CAUTION: This is the ANSI C (only) version of the Numerical Recipes
utility file complex.c. Do not confuse this file with the same-named
file complex.c that is supplied in the 'misc' subdirectory.
*That* file is the one from the book, and contains both ANSI and
traditional K&R versions, along with #ifdef macros to select the
correct version. *This* file contains only ANSI C. */
#include <math.h>
typedef struct FCOMPLEX {float r,i;} fcomplex;
fcomplex Cadd(fcomplex a, fcomplex b)
{
fcomplex c;
c.r=a.r+b.r;
c.i=a.i+b.i;
return c;
}
fcomplex Csub(fcomplex a, fcomplex b)
{
fcomplex c;
c.r=a.r-b.r;
c.i=a.i-b.i;
return c;
}
fcomplex Cmul(fcomplex a, fcomplex b)
{
fcomplex c;
c.r=a.r*b.r-a.i*b.i;
c.i=a.i*b.r+a.r*b.i;
return c;
}
fcomplex Complex(float re, float im)
{
fcomplex c;
c.r=re;
c.i=im;
return c;
}
fcomplex Conjg(fcomplex z)
{
fcomplex c;
c.r=z.r;
c.i = -z.i;
return c;
}
fcomplex Cdiv(fcomplex a, fcomplex b)
{
fcomplex c;
float r,den;
if (fabs(b.r) >= fabs(b.i)) {
r=b.i/b.r;
den=b.r+r*b.i;
c.r=(a.r+r*a.i)/den;
c.i=(a.i-r*a.r)/den;
} else {
r=b.r/b.i;
den=b.i+r*b.r;
c.r=(a.r*r+a.i)/den;
c.i=(a.i*r-a.r)/den;
}
return c;
}
float Cabs(fcomplex z)
{
float x,y,ans,temp;
x=fabs(z.r);
y=fabs(z.i);
if (x == 0.0)
ans=y;
else if (y == 0.0)
ans=x;
else if (x > y) {
temp=y/x;
ans=x*sqrt(1.0+temp*temp);
} else {
temp=x/y;
ans=y*sqrt(1.0+temp*temp);
}
return ans;
}
fcomplex Csqrt(fcomplex z)
{
fcomplex c;
float x,y,w,r;
if ((z.r == 0.0) && (z.i == 0.0)) {
c.r=0.0;
c.i=0.0;
return c;
} else {
x=fabs(z.r);
y=fabs(z.i);
if (x >= y) {
r=y/x;
w=sqrt(x)*sqrt(0.5*(1.0+sqrt(1.0+r*r)));
} else {
r=x/y;
w=sqrt(y)*sqrt(0.5*(r+sqrt(1.0+r*r)));
}
if (z.r >= 0.0) {
c.r=w;
c.i=z.i/(2.0*w);
} else {
c.i=(z.i >= 0) ? w : -w;
c.r=z.i/(2.0*c.i);
}
return c;
}
}
fcomplex RCmul(float x, fcomplex a)
{
fcomplex c;
c.r=x*a.r;
c.i=x*a.i;
return c;
}