ctan.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* INDENT OFF */
/*
* dcomplex ctan(dcomplex z);
*
* If z = x+iy, then since ctan(iz) = i*ctanh(z), we have
*
* ctan(z) = ctan((-1)*(-z)) = ctan(i*i*(-z))
* = i*ctanh(i*(-z)) = i*ctanh(i*(-x-yi))
* = i*ctanh(y-ix)
* = -Im(ctanh(y-ix))+i*Re(ctanh(y-ix))
*/
/* INDENT ON */
#include "libm.h"
#include "complex_wrapper.h"
double x, y;
x = D_RE(z);
y = D_IM(z);
D_RE(z) = y;
D_IM(z) = -x;
return (ans);
}