public final class ParallelRowMajorMatrix extends Matrix {
	private double[] elems ;
	
	public ParallelRowMajorMatrix(int rows, int cols) {
		super(rows, cols) ;
		elems = new double[rows * cols] ;
	}
	private int index(int i, int j) {
		return (i * cols) + j ;
	}
	public void set(int i, int j, double d) {
		elems[index(i, j)] = d ;
	}
	public double get(int i, int j) {
		return elems[index(i, j)] ;
	}
	public void multiplyLeft(double[] v, double[] out) {
		assert v.length == rows ;
		assert cols == out.length ;
		for (int i = 0 ; i < out.length ; ++i) out[i] = 0.0 ;
		for (int i = 0 ; i < rows ; ++i) {
			for (int j = 0 ; j < cols ; ++j) {
				out[j] += (v[i] * get(i, j)) ;
			}
		}
	}
	public void multiplyRight(double[] v, double[] out) {
		assert cols == v.length ;
		assert rows == out.length ;
		for (int i = 0 ; i < rows ; ++i) {
			double a = 0.0 ;
			for (int j = 0 ; j < cols ; ++j) {
				a = a + (get(i, j) * v[j]) ;
			}
			out[i] = a ;
		}
	}
}