/**
  * Copyright (c): Uwe Schmidt, FH Wedel
  *
  * You may study, modify and distribute this source code
  * FOR NON-COMMERCIAL PURPOSES ONLY.
  * This copyright message has to remain unchanged.
  *
  * Note that this document is provided 'as is',
  * WITHOUT WARRANTY of any kind either expressed or implied.
  */

#include "Matrix2.h"

#include <stdlib.h>

/*--------------------*/

Matrix newMatrix( int h, int w )
{
    Matrix res = malloc( h * sizeof( Row ) );

    if ( res ) {
	Row rows = malloc( h * w * sizeof( Element ) );

	if ( rows ) {
	    Matrix m = res;
	    Row r = rows;

	    while ( h-- ) {
		*m++ = r;
		r += w;
	    }

	    return res;
	}
    }
    /* heap overflow */
    exit( 1 );
}

/*--------------------*/

void freeMatrix( Matrix m )
{
    free( m[0] );
    free( m );
}

/*--------------------*/

Matrix zeroMatrix( int h, int w )
{
    Matrix res = newMatrix( h, w );

    int len = w * h;
    Row p = res[0];

    while ( len-- ) {
	*p++ = 0.0;
    }

    return res;
}

/*--------------------*/

Matrix unitMatrix( int h, int w )
{
    Matrix res = zeroMatrix( h, w );
    int i;

    for ( i = 0; i < w && i < h; ++i ) {
	res[i][i] = 1.0;
    }

    return res;
}

/*--------------------*/

Matrix addMatrix( Matrix m1, Matrix m2, int h, int w )
{

    Matrix res = newMatrix( h, w );
    int i, j;

    for ( i = 0; i < h; ++i ) {
	for ( j = 0; j < w; ++j ) {
	    res[i][j] = m1[i][j] + m2[i][j];
	}
    }

    return res;
}

/*--------------------*/

Matrix transposeMatrix( Matrix m, int h, int w )
{

    Matrix res = newMatrix( w, h );
    int i, j;

    for ( i = 0; i < h; ++i ) {
	for ( j = 0; j < w; ++j ) {
	    res[j][i] = m[i][j];
	}
    }

    return res;
}