man-pages/man3/clog.3

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.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
.\" Distributed under GPL
.\"
.TH CLOG 3 2002-07-28 "" "Linux Programmer's Manual"
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.SH NAME
clog, clogf, clogl \- natural logarithm of a complex number
.SH SYNOPSIS
.B #include <complex.h>
.sp
.BI "double complex clog(double complex " z );
.br
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.BI "float complex clogf(float complex " z );
.br
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.BI "long double complex clogl(long double complex " z );
.sp
Link with \fI-lm\fP.
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.SH DESCRIPTION
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The logarithm clog() is the inverse function of the exponential cexp().
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Thus, if y = clog(z), then z = cexp(y).
The imaginary part of
.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
Note that
.I z
close to zero will cause an overflow.
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.SH "CONFORMING TO"
C99
.SH "SEE ALSO"
.BR cabs (3),
.BR cexp (3),
.BR clog10 (3),
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.BR complex (7)