diff options
author | Eric Andersen <andersen@codepoet.org> | 2001-11-22 14:04:29 +0000 |
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committer | Eric Andersen <andersen@codepoet.org> | 2001-11-22 14:04:29 +0000 |
commit | 7ce331c01ce6eb7b3f5c715a38a24359da9c6ee2 (patch) | |
tree | 3a7e8476e868ae15f4da1b7ce26b2db6f434468c /libm/double/cmplx.c | |
parent | c117dd5fb183afb1a4790a6f6110d88704be6bf8 (diff) |
Totally rework the math library, this time based on the MacOs X
math library (which is itself based on the math lib from FreeBSD).
-Erik
Diffstat (limited to 'libm/double/cmplx.c')
-rw-r--r-- | libm/double/cmplx.c | 461 |
1 files changed, 0 insertions, 461 deletions
diff --git a/libm/double/cmplx.c b/libm/double/cmplx.c deleted file mode 100644 index dcd972bea..000000000 --- a/libm/double/cmplx.c +++ /dev/null @@ -1,461 +0,0 @@ -/* cmplx.c - * - * Complex number arithmetic - * - * - * - * SYNOPSIS: - * - * typedef struct { - * double r; real part - * double i; imaginary part - * }cmplx; - * - * cmplx *a, *b, *c; - * - * cadd( a, b, c ); c = b + a - * csub( a, b, c ); c = b - a - * cmul( a, b, c ); c = b * a - * cdiv( a, b, c ); c = b / a - * cneg( c ); c = -c - * cmov( b, c ); c = b - * - * - * - * DESCRIPTION: - * - * Addition: - * c.r = b.r + a.r - * c.i = b.i + a.i - * - * Subtraction: - * c.r = b.r - a.r - * c.i = b.i - a.i - * - * Multiplication: - * c.r = b.r * a.r - b.i * a.i - * c.i = b.r * a.i + b.i * a.r - * - * Division: - * d = a.r * a.r + a.i * a.i - * c.r = (b.r * a.r + b.i * a.i)/d - * c.i = (b.i * a.r - b.r * a.i)/d - * ACCURACY: - * - * In DEC arithmetic, the test (1/z) * z = 1 had peak relative - * error 3.1e-17, rms 1.2e-17. The test (y/z) * (z/y) = 1 had - * peak relative error 8.3e-17, rms 2.1e-17. - * - * Tests in the rectangle {-10,+10}: - * Relative error: - * arithmetic function # trials peak rms - * DEC cadd 10000 1.4e-17 3.4e-18 - * IEEE cadd 100000 1.1e-16 2.7e-17 - * DEC csub 10000 1.4e-17 4.5e-18 - * IEEE csub 100000 1.1e-16 3.4e-17 - * DEC cmul 3000 2.3e-17 8.7e-18 - * IEEE cmul 100000 2.1e-16 6.9e-17 - * DEC cdiv 18000 4.9e-17 1.3e-17 - * IEEE cdiv 100000 3.7e-16 1.1e-16 - */ -/* cmplx.c - * complex number arithmetic - */ - - -/* -Cephes Math Library Release 2.8: June, 2000 -Copyright 1984, 1995, 2000 by Stephen L. Moshier -*/ - - -#include <math.h> - -#ifdef ANSIPROT -extern double fabs ( double ); -extern double cabs ( cmplx * ); -extern double sqrt ( double ); -extern double atan2 ( double, double ); -extern double cos ( double ); -extern double sin ( double ); -extern double sqrt ( double ); -extern double frexp ( double, int * ); -extern double ldexp ( double, int ); -int isnan ( double ); -void cdiv ( cmplx *, cmplx *, cmplx * ); -void cadd ( cmplx *, cmplx *, cmplx * ); -#else -double fabs(), cabs(), sqrt(), atan2(), cos(), sin(); -double sqrt(), frexp(), ldexp(); -int isnan(); -void cdiv(), cadd(); -#endif - -extern double MAXNUM, MACHEP, PI, PIO2, INFINITY, NAN; -/* -typedef struct - { - double r; - double i; - }cmplx; -*/ -cmplx czero = {0.0, 0.0}; -extern cmplx czero; -cmplx cone = {1.0, 0.0}; -extern cmplx cone; - -/* c = b + a */ - -void cadd( a, b, c ) -register cmplx *a, *b; -cmplx *c; -{ - -c->r = b->r + a->r; -c->i = b->i + a->i; -} - - -/* c = b - a */ - -void csub( a, b, c ) -register cmplx *a, *b; -cmplx *c; -{ - -c->r = b->r - a->r; -c->i = b->i - a->i; -} - -/* c = b * a */ - -void cmul( a, b, c ) -register cmplx *a, *b; -cmplx *c; -{ -double y; - -y = b->r * a->r - b->i * a->i; -c->i = b->r * a->i + b->i * a->r; -c->r = y; -} - - - -/* c = b / a */ - -void cdiv( a, b, c ) -register cmplx *a, *b; -cmplx *c; -{ -double y, p, q, w; - - -y = a->r * a->r + a->i * a->i; -p = b->r * a->r + b->i * a->i; -q = b->i * a->r - b->r * a->i; - -if( y < 1.0 ) - { - w = MAXNUM * y; - if( (fabs(p) > w) || (fabs(q) > w) || (y == 0.0) ) - { - c->r = MAXNUM; - c->i = MAXNUM; - mtherr( "cdiv", OVERFLOW ); - return; - } - } -c->r = p/y; -c->i = q/y; -} - - -/* b = a - Caution, a `short' is assumed to be 16 bits wide. */ - -void cmov( a, b ) -void *a, *b; -{ -register short *pa, *pb; -int i; - -pa = (short *) a; -pb = (short *) b; -i = 8; -do - *pb++ = *pa++; -while( --i ); -} - - -void cneg( a ) -register cmplx *a; -{ - -a->r = -a->r; -a->i = -a->i; -} - -/* cabs() - * - * Complex absolute value - * - * - * - * SYNOPSIS: - * - * double cabs(); - * cmplx z; - * double a; - * - * a = cabs( &z ); - * - * - * - * DESCRIPTION: - * - * - * If z = x + iy - * - * then - * - * a = sqrt( x**2 + y**2 ). - * - * Overflow and underflow are avoided by testing the magnitudes - * of x and y before squaring. If either is outside half of - * the floating point full scale range, both are rescaled. - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * DEC -30,+30 30000 3.2e-17 9.2e-18 - * IEEE -10,+10 100000 2.7e-16 6.9e-17 - */ - - -/* -Cephes Math Library Release 2.1: January, 1989 -Copyright 1984, 1987, 1989 by Stephen L. Moshier -Direct inquiries to 30 Frost Street, Cambridge, MA 02140 -*/ - - -/* -typedef struct - { - double r; - double i; - }cmplx; -*/ - -#ifdef UNK -#define PREC 27 -#define MAXEXP 1024 -#define MINEXP -1077 -#endif -#ifdef DEC -#define PREC 29 -#define MAXEXP 128 -#define MINEXP -128 -#endif -#ifdef IBMPC -#define PREC 27 -#define MAXEXP 1024 -#define MINEXP -1077 -#endif -#ifdef MIEEE -#define PREC 27 -#define MAXEXP 1024 -#define MINEXP -1077 -#endif - - -double cabs( z ) -register cmplx *z; -{ -double x, y, b, re, im; -int ex, ey, e; - -#ifdef INFINITIES -/* Note, cabs(INFINITY,NAN) = INFINITY. */ -if( z->r == INFINITY || z->i == INFINITY - || z->r == -INFINITY || z->i == -INFINITY ) - return( INFINITY ); -#endif - -#ifdef NANS -if( isnan(z->r) ) - return(z->r); -if( isnan(z->i) ) - return(z->i); -#endif - -re = fabs( z->r ); -im = fabs( z->i ); - -if( re == 0.0 ) - return( im ); -if( im == 0.0 ) - return( re ); - -/* Get the exponents of the numbers */ -x = frexp( re, &ex ); -y = frexp( im, &ey ); - -/* Check if one number is tiny compared to the other */ -e = ex - ey; -if( e > PREC ) - return( re ); -if( e < -PREC ) - return( im ); - -/* Find approximate exponent e of the geometric mean. */ -e = (ex + ey) >> 1; - -/* Rescale so mean is about 1 */ -x = ldexp( re, -e ); -y = ldexp( im, -e ); - -/* Hypotenuse of the right triangle */ -b = sqrt( x * x + y * y ); - -/* Compute the exponent of the answer. */ -y = frexp( b, &ey ); -ey = e + ey; - -/* Check it for overflow and underflow. */ -if( ey > MAXEXP ) - { - mtherr( "cabs", OVERFLOW ); - return( INFINITY ); - } -if( ey < MINEXP ) - return(0.0); - -/* Undo the scaling */ -b = ldexp( b, e ); -return( b ); -} -/* csqrt() - * - * Complex square root - * - * - * - * SYNOPSIS: - * - * void csqrt(); - * cmplx z, w; - * - * csqrt( &z, &w ); - * - * - * - * DESCRIPTION: - * - * - * If z = x + iy, r = |z|, then - * - * 1/2 - * Im w = [ (r - x)/2 ] , - * - * Re w = y / 2 Im w. - * - * - * Note that -w is also a square root of z. The root chosen - * is always in the upper half plane. - * - * Because of the potential for cancellation error in r - x, - * the result is sharpened by doing a Heron iteration - * (see sqrt.c) in complex arithmetic. - * - * - * - * ACCURACY: - * - * Relative error: - * arithmetic domain # trials peak rms - * DEC -10,+10 25000 3.2e-17 9.6e-18 - * IEEE -10,+10 100000 3.2e-16 7.7e-17 - * - * 2 - * Also tested by csqrt( z ) = z, and tested by arguments - * close to the real axis. - */ - - -void csqrt( z, w ) -cmplx *z, *w; -{ -cmplx q, s; -double x, y, r, t; - -x = z->r; -y = z->i; - -if( y == 0.0 ) - { - if( x < 0.0 ) - { - w->r = 0.0; - w->i = sqrt(-x); - return; - } - else - { - w->r = sqrt(x); - w->i = 0.0; - return; - } - } - - -if( x == 0.0 ) - { - r = fabs(y); - r = sqrt(0.5*r); - if( y > 0 ) - w->r = r; - else - w->r = -r; - w->i = r; - return; - } - -/* Approximate sqrt(x^2+y^2) - x = y^2/2x - y^4/24x^3 + ... . - * The relative error in the first term is approximately y^2/12x^2 . - */ -if( (fabs(y) < 2.e-4 * fabs(x)) - && (x > 0) ) - { - t = 0.25*y*(y/x); - } -else - { - r = cabs(z); - t = 0.5*(r - x); - } - -r = sqrt(t); -q.i = r; -q.r = y/(2.0*r); -/* Heron iteration in complex arithmetic */ -cdiv( &q, z, &s ); -cadd( &q, &s, w ); -w->r *= 0.5; -w->i *= 0.5; -} - - -double hypot( x, y ) -double x, y; -{ -cmplx z; - -z.r = x; -z.i = y; -return( cabs(&z) ); -} |