Files
calc/commath.c
2017-05-21 15:38:25 -07:00

610 lines
9.8 KiB
C

/*
* Copyright (c) 1993 David I. Bell
* Permission is granted to use, distribute, or modify this source,
* provided that this copyright notice remains intact.
*
* Extended precision complex arithmetic primitive routines
*/
#include "cmath.h"
COMPLEX _czero_ = { &_qzero_, &_qzero_, 1 };
COMPLEX _cone_ = { &_qone_, &_qzero_, 1 };
COMPLEX _conei_ = { &_qzero_, &_qone_, 1 };
static COMPLEX _cnegone_ = { &_qnegone_, &_qzero_, 1 };
/*
* Add two complex numbers.
*/
COMPLEX *
cadd(COMPLEX *c1, COMPLEX *c2)
{
COMPLEX *r;
if (ciszero(c1))
return clink(c2);
if (ciszero(c2))
return clink(c1);
r = comalloc();
if (!qiszero(c1->real) || !qiszero(c2->real)) {
qfree(r->real);
r->real = qqadd(c1->real, c2->real);
}
if (!qiszero(c1->imag) || !qiszero(c2->imag)) {
qfree(r->imag);
r->imag = qqadd(c1->imag, c2->imag);
}
return r;
}
/*
* Subtract two complex numbers.
*/
COMPLEX *
csub(COMPLEX *c1, COMPLEX *c2)
{
COMPLEX *r;
if ((c1->real == c2->real) && (c1->imag == c2->imag))
return clink(&_czero_);
if (ciszero(c2))
return clink(c1);
r = comalloc();
if (!qiszero(c1->real) || !qiszero(c2->real)) {
qfree(r->real);
r->real = qsub(c1->real, c2->real);
}
if (!qiszero(c1->imag) || !qiszero(c2->imag)) {
qfree(r->imag);
r->imag = qsub(c1->imag, c2->imag);
}
return r;
}
/*
* Multiply two complex numbers.
* This saves one multiplication over the obvious algorithm by
* trading it for several extra additions, as follows. Let
* q1 = (a + b) * (c + d)
* q2 = a * c
* q3 = b * d
* Then (a+bi) * (c+di) = (q2 - q3) + (q1 - q2 - q3)i.
*/
COMPLEX *
cmul(COMPLEX *c1, COMPLEX *c2)
{
COMPLEX *r;
NUMBER *q1, *q2, *q3, *q4;
if (ciszero(c1) || ciszero(c2))
return clink(&_czero_);
if (cisone(c1))
return clink(c2);
if (cisone(c2))
return clink(c1);
if (cisreal(c2))
return cmulq(c1, c2->real);
if (cisreal(c1))
return cmulq(c2, c1->real);
/*
* Need to do the full calculation.
*/
r = comalloc();
q2 = qqadd(c1->real, c1->imag);
q3 = qqadd(c2->real, c2->imag);
q1 = qmul(q2, q3);
qfree(q2);
qfree(q3);
q2 = qmul(c1->real, c2->real);
q3 = qmul(c1->imag, c2->imag);
q4 = qqadd(q2, q3);
qfree(r->real);
r->real = qsub(q2, q3);
qfree(r->imag);
r->imag = qsub(q1, q4);
qfree(q1);
qfree(q2);
qfree(q3);
qfree(q4);
return r;
}
/*
* Square a complex number.
*/
COMPLEX *
csquare(COMPLEX *c)
{
COMPLEX *r;
NUMBER *q1, *q2;
if (ciszero(c))
return clink(&_czero_);
if (cisrunit(c))
return clink(&_cone_);
if (cisiunit(c))
return clink(&_cnegone_);
r = comalloc();
if (cisreal(c)) {
qfree(r->real);
r->real = qsquare(c->real);
return r;
}
if (cisimag(c)) {
qfree(r->real);
q1 = qsquare(c->imag);
r->real = qneg(q1);
qfree(q1);
return r;
}
q1 = qsquare(c->real);
q2 = qsquare(c->imag);
qfree(r->real);
r->real = qsub(q1, q2);
qfree(q1);
qfree(q2);
qfree(r->imag);
q1 = qmul(c->real, c->imag);
r->imag = qscale(q1, 1L);
qfree(q1);
return r;
}
/*
* Divide two complex numbers.
*/
COMPLEX *
cdiv(COMPLEX *c1, COMPLEX *c2)
{
COMPLEX *r;
NUMBER *q1, *q2, *q3, *den;
if (ciszero(c2)) {
math_error("Division by zero");
/*NOTREACHED*/
}
if ((c1->real == c2->real) && (c1->imag == c2->imag))
return clink(&_cone_);
r = comalloc();
if (cisreal(c1) && cisreal(c2)) {
qfree(r->real);
r->real = qqdiv(c1->real, c2->real);
return r;
}
if (cisimag(c1) && cisimag(c2)) {
qfree(r->real);
r->real = qqdiv(c1->imag, c2->imag);
return r;
}
if (cisimag(c1) && cisreal(c2)) {
qfree(r->imag);
r->imag = qqdiv(c1->imag, c2->real);
return r;
}
if (cisreal(c1) && cisimag(c2)) {
qfree(r->imag);
q1 = qqdiv(c1->real, c2->imag);
r->imag = qneg(q1);
qfree(q1);
return r;
}
if (cisreal(c2)) {
qfree(r->real);
qfree(r->imag);
r->real = qqdiv(c1->real, c2->real);
r->imag = qqdiv(c1->imag, c2->real);
return r;
}
q1 = qsquare(c2->real);
q2 = qsquare(c2->imag);
den = qqadd(q1, q2);
qfree(q1);
qfree(q2);
q1 = qmul(c1->real, c2->real);
q2 = qmul(c1->imag, c2->imag);
q3 = qqadd(q1, q2);
qfree(q1);
qfree(q2);
qfree(r->real);
r->real = qqdiv(q3, den);
qfree(q3);
q1 = qmul(c1->real, c2->imag);
q2 = qmul(c1->imag, c2->real);
q3 = qsub(q2, q1);
qfree(q1);
qfree(q2);
qfree(r->imag);
r->imag = qqdiv(q3, den);
qfree(q3);
qfree(den);
return r;
}
/*
* Invert a complex number.
*/
COMPLEX *
cinv(COMPLEX *c)
{
COMPLEX *r;
NUMBER *q1, *q2, *den;
if (ciszero(c)) {
math_error("Inverting zero");
/*NOTREACHED*/
}
r = comalloc();
if (cisreal(c)) {
qfree(r->real);
r->real = qinv(c->real);
return r;
}
if (cisimag(c)) {
q1 = qinv(c->imag);
qfree(r->imag);
r->imag = qneg(q1);
qfree(q1);
return r;
}
q1 = qsquare(c->real);
q2 = qsquare(c->imag);
den = qqadd(q1, q2);
qfree(q1);
qfree(q2);
qfree(r->real);
r->real = qqdiv(c->real, den);
q1 = qqdiv(c->imag, den);
qfree(r->imag);
r->imag = qneg(q1);
qfree(q1);
qfree(den);
return r;
}
/*
* Negate a complex number.
*/
COMPLEX *
cneg(COMPLEX *c)
{
COMPLEX *r;
if (ciszero(c))
return clink(&_czero_);
r = comalloc();
if (!qiszero(c->real)) {
qfree(r->real);
r->real = qneg(c->real);
}
if (!qiszero(c->imag)) {
qfree(r->imag);
r->imag = qneg(c->imag);
}
return r;
}
/*
* Take the integer part of a complex number.
* This means take the integer part of both components.
*/
COMPLEX *
cint(COMPLEX *c)
{
COMPLEX *r;
if (cisint(c))
return clink(c);
r = comalloc();
qfree(r->real);
r->real = qint(c->real);
qfree(r->imag);
r->imag = qint(c->imag);
return r;
}
/*
* Take the fractional part of a complex number.
* This means take the fractional part of both components.
*/
COMPLEX *
cfrac(COMPLEX *c)
{
COMPLEX *r;
if (cisint(c))
return clink(&_czero_);
r = comalloc();
qfree(r->real);
r->real = qfrac(c->real);
qfree(r->imag);
r->imag = qfrac(c->imag);
return r;
}
/*
* Take the conjugate of a complex number.
* This negates the complex part.
*/
COMPLEX *
cconj(COMPLEX *c)
{
COMPLEX *r;
if (cisreal(c))
return clink(c);
r = comalloc();
if (!qiszero(c->real)) {
qfree(r->real);
r->real = qlink(c->real);
}
qfree(r->imag);
r->imag = qneg(c->imag);
return r;
}
/*
* Return the real part of a complex number.
*/
COMPLEX *
creal(COMPLEX *c)
{
COMPLEX *r;
if (cisreal(c))
return clink(c);
r = comalloc();
if (!qiszero(c->real)) {
qfree(r->real);
r->real = qlink(c->real);
}
return r;
}
/*
* Return the imaginary part of a complex number as a real.
*/
COMPLEX *
cimag(COMPLEX *c)
{
COMPLEX *r;
if (cisreal(c))
return clink(&_czero_);
r = comalloc();
qfree(r->real);
r->real = qlink(c->imag);
return r;
}
/*
* Add a real number to a complex number.
*/
COMPLEX *
caddq(COMPLEX *c, NUMBER *q)
{
COMPLEX *r;
if (qiszero(q))
return clink(c);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qqadd(c->real, q);
r->imag = qlink(c->imag);
return r;
}
/*
* Subtract a real number from a complex number.
*/
COMPLEX *
csubq(COMPLEX *c, NUMBER *q)
{
COMPLEX *r;
if (qiszero(q))
return clink(c);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qsub(c->real, q);
r->imag = qlink(c->imag);
return r;
}
/*
* Shift the components of a complex number left by the specified
* number of bits. Negative values shift to the right.
*/
COMPLEX *
cshift(COMPLEX *c, long n)
{
COMPLEX *r;
if (ciszero(c) || (n == 0))
return clink(c);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qshift(c->real, n);
r->imag = qshift(c->imag, n);
return r;
}
/*
* Scale a complex number by a power of two.
*/
COMPLEX *
cscale(COMPLEX *c, long n)
{
COMPLEX *r;
if (ciszero(c) || (n == 0))
return clink(c);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qscale(c->real, n);
r->imag = qscale(c->imag, n);
return r;
}
/*
* Multiply a complex number by a real number.
*/
COMPLEX *
cmulq(COMPLEX *c, NUMBER *q)
{
COMPLEX *r;
if (qiszero(q))
return clink(&_czero_);
if (qisone(q))
return clink(c);
if (qisnegone(q))
return cneg(c);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qmul(c->real, q);
r->imag = qmul(c->imag, q);
return r;
}
/*
* Divide a complex number by a real number.
*/
COMPLEX *
cdivq(COMPLEX *c, NUMBER *q)
{
COMPLEX *r;
if (qiszero(q)) {
math_error("Division by zero");
/*NOTREACHED*/
}
if (qisone(q))
return clink(c);
if (qisnegone(q))
return cneg(c);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qqdiv(c->real, q);
r->imag = qqdiv(c->imag, q);
return r;
}
/*
* Construct a complex number given the real and imaginary components.
*/
COMPLEX *
qqtoc(NUMBER *q1, NUMBER *q2)
{
COMPLEX *r;
if (qiszero(q1) && qiszero(q2))
return clink(&_czero_);
r = comalloc();
qfree(r->real);
qfree(r->imag);
r->real = qlink(q1);
r->imag = qlink(q2);
return r;
}
/*
* Compare two complex numbers for equality, returning FALSE if they are equal,
* and TRUE if they differ.
*/
BOOL
ccmp(COMPLEX *c1, COMPLEX *c2)
{
BOOL i;
i = qcmp(c1->real, c2->real);
if (!i)
i = qcmp(c1->imag, c2->imag);
return i;
}
/*
* Compare two complex numbers and return a complex number with real and
* imaginary parts -1, 0 or 1 indicating relative values of the real and
* imaginary parts of the two numbers.
*/
COMPLEX *
crel(COMPLEX *c1, COMPLEX *c2)
{
COMPLEX *c;
c = comalloc();
qfree(c->real);
qfree(c->imag);
c->real = itoq((long) qrel(c1->real, c2->real));
c->imag = itoq((long) qrel(c1->imag, c2->imag));
return c;
}
/*
* Allocate a new complex number.
*/
COMPLEX *
comalloc(void)
{
COMPLEX *r;
r = (COMPLEX *) malloc(sizeof(COMPLEX));
if (r == NULL) {
math_error("Cannot allocate complex number");
/*NOTREACHED*/
}
r->links = 1;
r->real = qlink(&_qzero_);
r->imag = qlink(&_qzero_);
return r;
}
/*
* Free a complex number.
*/
void
comfree(COMPLEX *c)
{
if (--(c->links) > 0)
return;
qfree(c->real);
qfree(c->imag);
free(c);
}
/* END CODE */