2004-11-03 13:51:07 +00:00
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.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
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.\" Distributed under GPL
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.\"
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2008-08-11 17:13:47 +00:00
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.TH CARG 3 2008-08-11 "" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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2011-09-16 02:26:11 +00:00
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carg, cargf, cargl \- calculate the complex argument
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2004-11-03 13:51:07 +00:00
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.SH SYNOPSIS
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.B #include <complex.h>
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.sp
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.BI "double carg(double complex " z ");"
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2004-11-11 17:28:42 +00:00
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.br
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2004-11-03 13:51:07 +00:00
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.BI "float cargf(float complex " z ");"
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2004-11-11 17:28:42 +00:00
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.br
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2004-11-03 13:51:07 +00:00
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.BI "long double cargl(long double complex " z ");"
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.sp
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2007-07-21 05:25:03 +00:00
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Link with \fI\-lm\fP.
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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A complex number can be described by two real coordinates.
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2007-12-24 11:27:43 +00:00
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One may use rectangular coordinates and gets
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.nf
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z = x + I * y
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.fi
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where \fIx\ =\ creal(z)\fP and \fIy\ =\ cimag(z)\fP.
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2004-11-03 13:51:07 +00:00
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.LP
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2007-12-24 11:27:43 +00:00
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Or one may use polar coordinates and gets
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.nf
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z = r * cexp(I * a)
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.fi
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where \fIr\ =\ cabs(z)\fP
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is the "radius", the "modulus", the absolute value of \fIz\fP, and
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\fIa\ =\ carg(z)\fP
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is the "phase angle", the argument of \fIz\fP.
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2004-11-03 13:51:07 +00:00
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.LP
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2007-12-24 11:27:43 +00:00
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One has:
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.nf
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tan(carg(z)) = cimag(z) / creal(z)
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.fi
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2004-11-03 13:51:07 +00:00
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.SH "RETURN VALUE"
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2005-07-07 08:27:03 +00:00
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The return value is the range of [\-pi,pi].
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2008-08-11 17:13:47 +00:00
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.SH VERSIONS
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These functions first appeared in glibc in version 2.1.
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2004-11-03 13:51:07 +00:00
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.SH "CONFORMING TO"
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2008-07-15 13:39:17 +00:00
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C99.
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2004-11-03 13:51:07 +00:00
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.SH "SEE ALSO"
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.BR cabs (3),
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2006-04-21 01:24:06 +00:00
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.BR complex (7)
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