blob: 32d182aa200955aa9cb952bf285b3da5e41c61d5 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
.\" 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 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)
|
