www.LinuxHowtos.org howtos, tips&tricks and tutorials for linux
from small one page howto to huge articles all in one place

search text in:

Poll
What does your sytem tell when running "ulimit -u"?

poll results

using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

159693

userrating:

average rating: 1.8 (88 votes) (1=very good 6=terrible)

May 25th. 2007:
Words

486

Views

247282

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

130715

userrating:

average rating: 1.3 (28 votes) (1=very good 6=terrible)

April, 26th. 2006:

You are here: manpages

# COMPLEX

Section: Linux Programmer's Manual (7)
Updated: 2011-09-16

## NAME

complex - basics of complex mathematics

## SYNOPSIS

#include <complex.h>

## DESCRIPTION

Complex numbers are numbers of the form z = a+b*i, where a and b are real numbers and i = sqrt(-1), so that i*i = -1.

There are other ways to represent that number. The pair (a,b) of real numbers may be viewed as a point in the plane, given by X- and Y-coordinates. This same point may also be described by giving the pair of real numbers (r,phi), where r is the distance to the origin O, and phi the angle between the X-axis and the line Oz. Now z = r*exp(i*phi) = r*(cos(phi)+i*sin(phi)).

The basic operations are defined on z = a+b*i and w = c+d*i as:

addition: z+w = (a+c) + (b+d)*i
multiplication: z*w = (a*c - b*d) + (a*d + b*c)*i
division: z/w = ((a*c + b*d)/(c*c + d*d)) + ((b*c - a*d)/(c*c + d*d))*i

Nearly all math function have a complex counterpart but there are some complex-only functions.

## EXAMPLE

Your C-compiler can work with complex numbers if it supports the C99 standard. Link with -lm. The imaginary unit is represented by I.

/* check that exp(i * pi) == -1 */ #include <math.h> /* for atan */ #include <stdio.h> #include <complex.h>

int main(void) {
double pi = 4 * atan(1.0);
double complex z = cexp(I * pi);
printf("%f + %f * i\n", creal(z), cimag(z)); }

cabs(3), cacos(3), cacosh(3), carg(3), casin(3), casinh(3), catan(3), catanh(3), ccos(3), ccosh(3), cerf(3), cexp(3), cexp2(3), cimag(3), clog(3), clog10(3), clog2(3), conj(3), cpow(3), cproj(3), creal(3), csin(3), csinh(3), csqrt(3), ctan(3), ctanh(3)

NAME
SYNOPSIS
DESCRIPTION
EXAMPLE