/*
 *  Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
 *  Copyright (C) 2008 - INRIA - Arnaud TORSET
 *
 *  This file must be used under the terms of the CeCILL.
 *  This source file is licensed as described in the file COPYING, which
 *  you should have received as part of this distribution.  The terms
 *  are also available at
 *  http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
 *
 */
 
#include <stdlib.h>
#include "spec.h"
#include "lapack.h"
#include "zeros.h"
#include "max.h"

void dspec2a(double* in, int rows,double* eigenvalues,double* eigenvectors){
	int i=0, j=0, ij=0, ij1=0;
	int symmetric=0;
	int INFO=0;
	int iWorkSize = 0;
	double* pdblWork;
	double* outReal;
	double* outImag;
	double* pdblLeftvectors;
	double* pdblRightvectors;
	double* inCopy;
	
	/* FIXME : malloc here */
	inCopy = (double*)malloc((unsigned int)(rows*rows) * sizeof(double));
	outReal = (double*)malloc((unsigned int)rows * sizeof(double));
	outImag = NULL;
	pdblLeftvectors=NULL;
	pdblRightvectors=NULL;
	
	
	iWorkSize = 4*rows;
	pdblWork = (double*)malloc((unsigned int)iWorkSize * sizeof(double));
	
	for(i=0;i<rows*rows;i++)	inCopy[i]=in[i];
	
	
	
	/* look if the matrix is symmetric */
	for (i=0;i<rows;i++){	
		for (j=0;j<rows;j++) 	
			if (in[i*rows+j]!=in[i+j*rows]) break;
		if (j!=rows) break;
		
	}
	
	/* the matrix is symmetric if the 2 loops goes to end i.e
		i==rows and j==rows */
	if ((i==rows)&&(j==rows)) symmetric=1;
	
	/* apply lapack function according to symmetry */
	if(symmetric){	
		C2F(dsyev)( "V", "U", &rows, inCopy, &rows, outReal, pdblWork, &iWorkSize, &INFO );
	
		/* Computation of eigenvectors */
		for (i=0;i<rows*rows;i++) 	eigenvectors[i] = inCopy[i];
	}
	else {	
		pdblRightvectors=(double*)malloc((unsigned int)(rows*rows) * sizeof(double));
		outImag = (double*)malloc((unsigned int)rows * sizeof(double));
		C2F(dgeev)( "N", "V", &rows, inCopy, &rows, outReal, outImag,
        			pdblLeftvectors, &rows, pdblRightvectors, &rows, pdblWork, &iWorkSize, &INFO );  
	
		/* Computation of eigenvectors */        			
        	j=0;
		while (j<rows)
		{
			if (outImag[j]==0)
			{	
				for(i = 0 ; i < rows ; i++)
				{
					ij = i + j * rows;
					eigenvectors[ij] = pdblRightvectors[ij];
				}
				j = j + 1;
			}
			else
			{
				for(i = 0 ; i < rows ; i++)
				{
					ij = i + j * rows;
					ij1 = i + (j + 1) * rows;
					eigenvectors[ij] = pdblRightvectors[ij];
					eigenvectors[ij1] = pdblRightvectors[ij];
				}
				j = j + 2;
			}
		}
	}
	
	/* Computation of eigenvalues */
	dzerosa(eigenvalues,1,rows*rows);
	for (i=0;i<rows;i++) eigenvalues[i+i*rows]=outReal[i];
	

	

	free(inCopy);
	free(outReal);
	free(outImag);
	free(pdblLeftvectors);
	free(pdblRightvectors);
	free(pdblWork);

}