/*
 * complex.c
 *
 * This file contains C functions implementing a partial complex
 * arithmetic package.  The functions operate on abstract arrays of
 * complex numbers stored as floats, with the real parts in the even
 * indices and the imaginary parts in the odd indices.
 */

#include <math.h>
#include "complex.h"

/*
 * Return the real part of the n'th complex number in the array
 */
float get_real_part (float cv[], int n) {
	return cv[n*2];
}

/*
 * Return the imaginary part of the n'th complex number in the array
 */
float get_imag_part (float cv[], int n) {
	return cv[n*2+1];
}

/*
 * Set the real part of the n'th complex number equal to 'val'
 */
void set_real_part (float cv[], int n, float val) {
	cv[n*2] = val;
}

/*
 * Set the imaginary part of the n'th complex number equal to 'val'
 */
void set_imag_part (float cv[], int n, float val) {
	cv[n*2+1] = val;
}

/*
 * Return the magnitude (i.e., distance from the origin in the 
 * complex plane) of the n'th complex number.
 */
float magnitude (float cv[], int n) {
	float	rp, ip, sq;

	rp = get_real_part (cv, n);
	ip = get_imag_part (cv, n);
	sq = rp * rp + ip * ip;
	return (float) sqrt (sq);
}

/*
 * Scalar multiply the n'th number by a float, placing the value
 * back into the array
 */

float scalar_mult (float cv[], int n, float r) {
	cv[n*2] *= r;
	cv[n*2+1] *= r;
}