public static DoubleMatrix copy(DoubleMatrix x, DoubleMatrix y) {
		//NativeBlas.dcopy(x.length, x.data, 0, 1, y.data, 0, 1);
		JavaBlas.rcopy(x.length, x.data, 0, 1, y.data, 0, 1);
		return y;
	}
public static DoubleMatrix copy ( DoubleMatrix x , DoubleMatrix y ) { JavaBlas . rcopy ( x . length , x . data , 0 , 1 , y . data , 0 , 1 ) ; return y ; }
Compute y <- x (copy a matrix)