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COMPLEX
Section: Linux Programmer's Manual (7)
Updated: 2002-07-28
Index
Return to Main Contents
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 <complex.h>
int
main(void)
{
double pi = 4 * atan(1.0);
complex z = cexp(I * pi);
printf("%f + %f * i\n", creal(z), cimag(z));
}
SEE ALSO
cabs(3),
carg(3),
cexp(3),
cimag(3),
creal(3)
COLOPHON
This page is part of release 3.05 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- EXAMPLE
-
- SEE ALSO
-
- COLOPHON
-
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