/*
 * basis.c
 *
 * Handle basis structures
 *
 * (c) 2007 Thomas White <taw27@cam.ac.uk>
 *
 *  dtr - Diffraction Tomography Reconstruction
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <math.h>

#include "reflections.h"
#include "basis.h"

static double basis_efom(ReflectionList *reflectionlist, Basis *basis) {

	int n_indexed, n_counted;
	Reflection *cur;
	
	cur = reflectionlist->reflections;
	n_indexed = 0;
	n_counted = 0;
	while ( cur ) {

		if ( cur->type == REFLECTION_NORMAL ) {
			
			/* Can this basis "approximately" account for this reflection? */
			double det;
			double a11, a12, a13, a21, a22, a23, a31, a32, a33;
			double h, k, l;
			
			/* Set up the coordinate transform from hkl to xyz */
			a11 = basis->a.x;  a12 = basis->a.y;  a13 = basis->a.z;
			a21 = basis->b.x;  a22 = basis->b.y;  a23 = basis->b.z;
			a31 = basis->c.x;  a32 = basis->c.y;  a33 = basis->c.z;
			
			/* Invert the matrix to get hkl from xyz */
			det = a11*(a22*a33 - a23*a32) - a12*(a21*a33 - a23*a31) + a13*(a21*a32 - a22*a31);
			h = ((a22*a33-a23*a32)*cur->x + (a23*a31-a21*a33)*cur->y + (a21*a32-a22*a31)*cur->z) / det;
			k = ((a13*a32-a12*a33)*cur->x + (a11*a33-a13*a31)*cur->y + (a12*a31-a11*a32)*cur->z) / det;
			l = ((a12*a23-a13*a22)*cur->x + (a13*a21-a11*a23)*cur->y + (a11*a22-a12*a21)*cur->z) / det;
			
			/* Calculate the deviations in terms of |a|, |b| and |c| */
			h = fabs(h);  k = fabs(k);  l = fabs(l);
			h -= floor(h);  k -= floor(k);  l -= floor(l);
			if ( h == 1.0 ) h = 0.0;
			if ( k == 1.0 ) k = 0.0;
			if ( l == 1.0 ) l = 0.0;
			
			/* Define "approximately" here.  Circle in basis space becomes an ellipsoid in reciprocal space */
			if ( h*h + k*k + l*l <= 0.1*0.1*0.1 ) n_indexed++;
			
			n_counted++;
		
		}
		
		cur = cur->next;

	}
	
	return (double)n_indexed / n_counted;

}