public static double deltaMatrices(
	double[][] mat1,
	double[][] mat2 )
{
	double[][] test = Matrix.sub(mat1, mat2);
	double delta = 0.0;
	int m = Matrix.getNumOfRows(mat1);
	int n = Matrix.getNumOfColumns(mat1);
	for ( int i = 0; i < m; ++i )
		for ( int j = 0; j < n; ++j )
			delta += Math.abs(test[i][j]);
	return(delta / (m * n));
}