man3/catanh.3

   1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
   2 .\" and Copyright (C) 2011 Michael Kerrisk <mtk.manpages@gmail.com>
   3 .\"
   4 .\" SPDX-License-Identifier: GPL-1.0-or-later
   5 .\"
   6 .TH catanh 3 (date) "Linux man-pages (unreleased)"
   7 .SH NAME
   8 catanh, catanhf, catanhl \- complex arc tangents hyperbolic
   9 .SH LIBRARY
  10 Math library
  11 .RI ( libm ", " \-lm )
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <complex.h>
  15 .PP
  16 .BI "double complex catanh(double complex " z );
  17 .BI "float complex catanhf(float complex " z );
  18 .BI "long double complex catanhl(long double complex " z );
  19 .fi
  20 .SH DESCRIPTION
  21 These functions calculate the complex arc hyperbolic tangent of
  22 .IR z .
  23 If \fIy\~=\~catanh(z)\fP, then \fIz\~=\~ctanh(y)\fP.
  24 The imaginary part of
  25 .I y
  26 is chosen in the interval [\-pi/2,pi/2].
  27 .PP
  28 One has:
  29 .PP
  30 .in +4n
  31 .EX
  32 catanh(z) = 0.5 * (clog(1 + z) \- clog(1 \- z))
  33 .EE
  34 .in
  35 .SH VERSIONS
  36 These functions first appeared in glibc in version 2.1.
  37 .SH ATTRIBUTES
  38 For an explanation of the terms used in this section, see
  39 .BR attributes (7).
  40 .ad l
  41 .nh
  42 .TS
  43 allbox;
  44 lbx lb lb
  45 l l l.
  46 Interface       Attribute       Value
  47 T{
  48 .BR catanh (),
  49 .BR catanhf (),
  50 .BR catanhl ()
  51 T}      Thread safety   MT-Safe
  52 .TE
  53 .hy
  54 .ad
  55 .sp 1
  56 .SH STANDARDS
  57 C99, POSIX.1-2001, POSIX.1-2008.
  58 .SH EXAMPLES
  59 .\" SRC BEGIN (catanh.c)
  60 .EX
  61 /* Link with "\-lm" */
  62
  63 #include <complex.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <unistd.h>
  67
  68 int
  69 main(int argc, char *argv[])
  70 {
  71     double complex z, c, f;
  72
  73     if (argc != 3) {
  74         fprintf(stderr, "Usage: %s <real> <imag>\en", argv[0]);
  75         exit(EXIT_FAILURE);
  76     }
  77
  78     z = atof(argv[1]) + atof(argv[2]) * I;
  79
  80     c = catanh(z);
  81     printf("catanh() = %6.3f %6.3f*i\en", creal(c), cimag(c));
  82
  83     f = 0.5 * (clog(1 + z) \- clog(1 \- z));
  84     printf("formula  = %6.3f %6.3f*i\en", creal(f), cimag(f));
  85
  86     exit(EXIT_SUCCESS);
  87 }
  88 .EE
  89 .\" SRC END
  90 .SH SEE ALSO
  91 .BR atanh (3),
  92 .BR cabs (3),
  93 .BR cimag (3),
  94 .BR ctanh (3),
  95 .BR complex (7)