mirror of https://github.com/mkerrisk/man-pages
39 lines
862 B
Groff
39 lines
862 B
Groff
.\" 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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.TH CLOG 3 2002-07-28 "" "Linux Programmer's Manual"
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.SH NAME
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clog, clogf, clogl \- natural logarithm of a complex number
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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 complex clog(double complex " z );
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.br
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.BI "float complex clogf(float complex " z );
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.br
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.BI "long double complex clogl(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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The logarithm
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.BR clog ()
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is the inverse function of the exponential
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.BR cexp (3).
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Thus, if y = clog(z), then z = cexp(y).
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The imaginary part of
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.I y
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is chosen in the interval [\-pi,pi].
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.LP
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One has clog(z) = log(cabs(z)) + I * carg(z).
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.LP
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Note that
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.I z
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close to zero will cause an overflow.
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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 cexp (3),
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.BR clog10 (3),
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.BR complex (7)
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