code: public static FloatMatrix swap(FloatMatrix x, FloatMatrix y) {
  		//NativeBlas.sswap(x.length, x.data, 0, 1, y.data, 0, 1);
  		JavaBlas.rswap(x.length, x.data, 0, 1, y.data, 0, 1);
  		return y;
  	}
docs: Compute x &lt;-&gt; y (swap two matrices)