home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Language/OS - Multiplatform Resource Library
/
LANGUAGE OS.iso
/
f2c
/
may_5_92.lha
/
f2c.VMay_5_1992
/
libF77
/
pow_zi.c
< prev
next >
Wrap
C/C++ Source or Header
|
1992-05-07
|
518b
|
47 lines
#include "f2c.h"
VOID pow_zi(p, a, b) /* p = a**b */
doublecomplex *p, *a;
integer *b;
{
integer n;
double t;
doublecomplex x;
static doublecomplex one = {1.0, 0.0};
n = *b;
p->r = 1;
p->i = 0;
if(n == 0)
return;
if(n < 0)
{
n = -n;
z_div(&x, &one, a);
}
else
{
x.r = a->r;
x.i = a->i;
}
for( ; ; )
{
if(n & 01)
{
t = p->r * x.r - p->i * x.i;
p->i = p->r * x.i + p->i * x.r;
p->r = t;
}
if(n >>= 1)
{
t = x.r * x.r - x.i * x.i;
x.i = 2 * x.r * x.i;
x.r = t;
}
else
break;
}
}