| .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) |
| .\" Distributed under GPL |
| .\" |
| .TH CARG 3 2008-08-11 "" "Linux Programmer's Manual" |
| .SH NAME |
| carg, cargf, cargl \- calculate the complex argument |
| .SH SYNOPSIS |
| .B #include <complex.h> |
| .sp |
| .BI "double carg(double complex " z ");" |
| .br |
| .BI "float cargf(float complex " z ");" |
| .br |
| .BI "long double cargl(long double complex " z ");" |
| .sp |
| Link with \fI\-lm\fP. |
| .SH DESCRIPTION |
| A complex number can be described by two real coordinates. |
| One may use rectangular coordinates and gets |
| |
| .nf |
| z = x + I * y |
| .fi |
| |
| where \fIx\ =\ creal(z)\fP and \fIy\ =\ cimag(z)\fP. |
| .LP |
| Or one may use polar coordinates and gets |
| .nf |
| |
| z = r * cexp(I * a) |
| |
| .fi |
| where \fIr\ =\ cabs(z)\fP |
| is the "radius", the "modulus", the absolute value of \fIz\fP, and |
| \fIa\ =\ carg(z)\fP |
| is the "phase angle", the argument of \fIz\fP. |
| .LP |
| One has: |
| .nf |
| |
| tan(carg(z)) = cimag(z) / creal(z) |
| .fi |
| .SH "RETURN VALUE" |
| The return value is the range of [\-pi,pi]. |
| .SH VERSIONS |
| These functions first appeared in glibc in version 2.1. |
| .SH "CONFORMING TO" |
| C99. |
| .SH "SEE ALSO" |
| .BR cabs (3), |
| .BR complex (7) |
