xref: /illumos-gate/usr/src/lib/libm/common/complex/csin.c (revision ddc0e0b5)
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2125c28e83SPiotr Jasiukajtis 
2225c28e83SPiotr Jasiukajtis /*
2325c28e83SPiotr Jasiukajtis  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
2425c28e83SPiotr Jasiukajtis  */
2525c28e83SPiotr Jasiukajtis /*
2625c28e83SPiotr Jasiukajtis  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
2725c28e83SPiotr Jasiukajtis  * Use is subject to license terms.
2825c28e83SPiotr Jasiukajtis  */
2925c28e83SPiotr Jasiukajtis 
30*ddc0e0b5SRichard Lowe #pragma weak __csin = csin
3125c28e83SPiotr Jasiukajtis 
3225c28e83SPiotr Jasiukajtis /* INDENT OFF */
3325c28e83SPiotr Jasiukajtis /*
3425c28e83SPiotr Jasiukajtis  * dcomplex csin(dcomplex z);
3525c28e83SPiotr Jasiukajtis  *
3625c28e83SPiotr Jasiukajtis  * If z = x+iy, then since csin(iz) = i*csinh(z),  we have
3725c28e83SPiotr Jasiukajtis  *
3825c28e83SPiotr Jasiukajtis  * csin(z)	= csin((-1)*(-z)) = csin(i*i*(-z))
3925c28e83SPiotr Jasiukajtis  *		= i*csinh(i*(-z)) = i*csinh(i*(-x-yi))
4025c28e83SPiotr Jasiukajtis  *		= i*csinh(y-ix)
4125c28e83SPiotr Jasiukajtis  *		= -Im(csinh(y-ix))+i*Re(csinh(y-ix))
4225c28e83SPiotr Jasiukajtis  */
4325c28e83SPiotr Jasiukajtis /* INDENT ON */
4425c28e83SPiotr Jasiukajtis 
4525c28e83SPiotr Jasiukajtis #include "libm.h"
4625c28e83SPiotr Jasiukajtis #include "complex_wrapper.h"
4725c28e83SPiotr Jasiukajtis 
4825c28e83SPiotr Jasiukajtis dcomplex
csin(dcomplex z)4925c28e83SPiotr Jasiukajtis csin(dcomplex z) {
5025c28e83SPiotr Jasiukajtis 	double x, y;
5125c28e83SPiotr Jasiukajtis 	dcomplex ans, ct;
5225c28e83SPiotr Jasiukajtis 
5325c28e83SPiotr Jasiukajtis 	x = D_RE(z);
5425c28e83SPiotr Jasiukajtis 	y = D_IM(z);
5525c28e83SPiotr Jasiukajtis 	D_RE(z) = y;
5625c28e83SPiotr Jasiukajtis 	D_IM(z) = -x;
5725c28e83SPiotr Jasiukajtis 	ct = csinh(z);
5825c28e83SPiotr Jasiukajtis 	D_RE(ans) = -D_IM(ct);
5925c28e83SPiotr Jasiukajtis 	D_IM(ans) = D_RE(ct);
6025c28e83SPiotr Jasiukajtis 	return (ans);
6125c28e83SPiotr Jasiukajtis }
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