complex.c

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/*
 *	*************************************************************************
 *	*									*
 *	*	This confidential and proprietary software may be used only	*
 *	*  as authorized by a licensing agreement from the Alta Group of	*
 *	*  Cadence Design Systems, Inc.  In the event of publication, the	*
 *	*  following notice is applicable:					*
 *	*									*
 *	*    (c) COPYRIGHT 1995 ALTA GROUP OF CADENCE DESIGN SYSTEMS, INC.	*
 *	*			ALL RIGHTS RESERVED				*
 *	*									*
 *	*	The entire notice above must be reproduced on all authorized	*
 *	*  copies.								*
 *	*									*
 *	*************************************************************************
 *
 */
/*
 * FILE:  complex.c
 * DATE:  Feb. 19, 1990
 * RELATED FILES:  
 * AUTHOR:  John Lundell
 * DESCRIPTION:  
 *	Complex math support functions
 *
 * NOTES/WARNINGS:  
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
#include "cgs.h"

/*
 *  Functions
 */
/*---------------------------------------------------------------
 * FUNCTION:  c_add
 * DESCRIPTION:  
 *	Add two complex numbers
 *
 * RETURN VALUE:  The complex sum
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
Complex c_add(s_c1, s_c2)
Complex	s_c1, s_c2;
{
	s_c1.real += s_c2.real;
	s_c1.imag += s_c2.imag;

	return s_c1;

}


/*---------------------------------------------------------------
 * FUNCTION:  c_sub
 * DESCRIPTION:  
 *	Subtract two complex numbers.
 *
 * RETURN VALUE:  The complex difference
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
Complex c_sub(s_c1, s_c2)
Complex s_c1, s_c2;
{
	s_c1.real -= s_c2.real;
	s_c1.imag -= s_c2.imag;

	return s_c1;
}

/*---------------------------------------------------------------
 * FUNCTION:  c_conj
 * DESCRIPTION:  
 *	Take the complex conjugate of a complex number
 *
 * RETURN VALUE:  The complex conjugate.
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
Complex c_conj(s_c)
Complex s_c;
{
	s_c.imag = -s_c.imag;

	return s_c;
}


/*---------------------------------------------------------------
 * FUNCTION:  c_mag
 * DESCRIPTION:  
 *	Take the complex magnitude.
 *
 * RETURN VALUE:  The complex magnitude.
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
double c_mag(s_c)
Complex	s_c;
{
	return sqrt(s_c.real * s_c.real + s_c.imag * s_c.imag);
}

	
/*---------------------------------------------------------------
 * FUNCTION:  c_mul
 * DESCRIPTION:  
 * 	Multiply two complex numbers
 *
 * RETURN VALUE:  The complex product.
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
Complex c_mul(s_c1, s_c2)
Complex s_c1, s_c2;
{
	Complex	ret;

	ret.real = s_c1.real * s_c2.real - s_c1.imag * s_c2.imag;
	ret.imag = s_c1.real * s_c2.imag + s_c1.imag * s_c2.real;

	return ret;
}


/*---------------------------------------------------------------
 * FUNCTION:  c_dvd
 * DESCRIPTION:  
 *	Divide two complex numbers
 *
 * RETURN VALUE:  The complex quotient
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
Complex c_dvd(s_c1, s_c2)
Complex	s_c1, s_c2;
{
	Complex	ret;
	double	den = 1.0 / (s_c2.real * s_c2.real + s_c2.imag * s_c2.imag);

	ret.real = (s_c1.real * s_c2.real + s_c1.imag * s_c2.imag) * den;
	ret.imag = (s_c1.imag * s_c2.real - s_c1.real * s_c2.imag) * den;

	return ret;
}


/*---------------------------------------------------------------
 * FUNCTION:  c_sqrt
 * DESCRIPTION:  
 *	Square root of a complex number.
 *
 * RETURN VALUE:  Complex square root.
 * NOTES/WARNINGS: 
 * REVISION HISTORY:
 *	Release		Who	Date	Comments
 */
Complex c_sqrt(s_v)
Complex	s_v;
{
	double theta = 0.5 * atan2(s_v.imag, s_v.real);
	double radius = sqrt(sqrt(s_v.real * s_v.real + s_v.imag * s_v.imag));
/*
 *  Get the square root from the complex plane value
 */
	s_v.real = radius * cos(theta);
	s_v.imag = radius * sin(theta);

	return s_v;
}