complex — basics of complex mathematics
#include <complex.h>
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:
Nearly all math function have a complex counterpart but there are some complex-only functions.
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)); }
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Copyright 2002 Walter Harms (walter.harmsinformatik.uni-oldenburg.de) Distributed under GPL |