mirror of https://github.com/mkerrisk/man-pages
62 lines
1.2 KiB
Groff
62 lines
1.2 KiB
Groff
.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
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.\"
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.\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
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.\" Distributed under GPL
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.\" %%%LICENSE_END
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.\"
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.TH CARG 3 2008-08-11 "" "Linux Programmer's Manual"
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.SH NAME
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carg, cargf, cargl \- calculate the complex argument
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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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.br
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.BI "float cargf(float complex " z ");"
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.br
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.BI "long double cargl(long double complex " z ");"
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.sp
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Link with \fI\-lm\fP.
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.SH DESCRIPTION
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A complex number can be described by two real coordinates.
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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
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.IR "x\ =\ creal(z)"
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and
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.IR "y\ =\ cimag(z)" .
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.LP
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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
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.IR "r\ =\ cabs(z)"
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is the "radius", the "modulus", the absolute value of
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.IR z ,
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and
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.IR "a\ =\ carg(z)"
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is the "phase angle", the argument of
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.IR z .
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.LP
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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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.SH RETURN VALUE
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The return value is the range of [\-pi,pi].
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.SH VERSIONS
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These functions first appeared in glibc in version 2.1.
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.SH CONFORMING TO
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C99.
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.SH SEE ALSO
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.BR cabs (3),
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.BR complex (7)
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