| .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) |
| .\" and Copyright (C) 2011 Michael Kerrisk <mtk.manpages@gmail.com> |
| .\" |
| .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE) |
| .\" Distributed under GPL |
| .\" %%%LICENSE_END |
| .\" |
| .TH CATAN 3 2019-03-06 "" "Linux Programmer's Manual" |
| .SH NAME |
| catan, catanf, catanl \- complex arc tangents |
| .SH SYNOPSIS |
| .B #include <complex.h> |
| .PP |
| .BI "double complex catan(double complex " z ); |
| .br |
| .BI "float complex catanf(float complex " z ); |
| .br |
| .BI "long double complex catanl(long double complex " z ); |
| .PP |
| Link with \fI\-lm\fP. |
| .SH DESCRIPTION |
| These functions calculate the complex arc tangent of |
| .IR z . |
| If \fIy\ =\ catan(z)\fP, then \fIz\ =\ ctan(y)\fP. |
| The real part of y is chosen in the interval [\-pi/2,pi/2]. |
| .PP |
| One has: |
| .PP |
| .nf |
| catan(z) = (clog(1 + i * z) \- clog(1 \- i * z)) / (2 * i) |
| .fi |
| .SH VERSIONS |
| These functions first appeared in glibc in version 2.1. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lbw27 lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR catan (), |
| .BR catanf (), |
| .BR catanl () |
| T} Thread safety MT-Safe |
| .TE |
| .SH CONFORMING TO |
| C99, POSIX.1-2001, POSIX.1-2008. |
| .SH EXAMPLE |
| .EX |
| /* Link with "\-lm" */ |
| |
| #include <complex.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <stdio.h> |
| |
| int |
| main(int argc, char *argv[]) |
| { |
| double complex z, c, f; |
| double complex i = I; |
| |
| if (argc != 3) { |
| fprintf(stderr, "Usage: %s <real> <imag>\en", argv[0]); |
| exit(EXIT_FAILURE); |
| } |
| |
| z = atof(argv[1]) + atof(argv[2]) * I; |
| |
| c = catan(z); |
| printf("catan() = %6.3f %6.3f*i\en", creal(c), cimag(c)); |
| |
| f = (clog(1 + i * z) \- clog(1 \- i * z)) / (2 * i); |
| printf("formula = %6.3f %6.3f*i\en", creal(f2), cimag(f2)); |
| |
| exit(EXIT_SUCCESS); |
| } |
| .EE |
| .SH SEE ALSO |
| .BR ccos (3), |
| .BR clog (3), |
| .BR ctan (3), |
| .BR complex (7) |