CATAN

Section: Linux Programmer's Manual (3)
Updated: 2015-04-19
Index Return to Main Contents

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NAME

catan, catanf, catanl - complex arc tangents  

SYNOPSIS

#include <complex.h>

double complex catan(double complex z);
float complex catanf(float complex z);
long double complex catanl(long double complex z);

Link with -lm.  

DESCRIPTION

These functions calculate the complex arc tangent of z. If y = catan(z), then z = ctan(y). The real part of y is chosen in the interval [-pi/2,pi/2].

One has:

    catan(z) = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i)

 

VERSIONS

These functions first appeared in glibc in version 2.1.  

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
catan(), catanf(), catanl()	Thread safety	MT-Safe

 

CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.  

EXAMPLE

/* 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>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    z = atof(argv[1]) + atof(argv[2]) * I;

    c = catan(z);
    printf("catan() = %6.3f %6.3f*i\n", creal(c), cimag(c));

    f = (clog(1 + i * z) - clog(1 - i * z)) / (2 * i);
    printf("formula = %6.3f %6.3f*i\n", creal(f2), cimag(f2));

    exit(EXIT_SUCCESS); }  

SEE ALSO

ccos(3), clog(3), ctan(3), complex(7)  

COLOPHON

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Index

NAME

SYNOPSIS

DESCRIPTION

VERSIONS

ATTRIBUTES

CONFORMING TO

EXAMPLE

SEE ALSO

COLOPHON