@Test
public void rowMeans() {
DoubleArrayVector a = new DoubleArrayVector(1,2,3,4,5,6,7,8,9,10,11,12 );
DeferredRowMeans rowMeans = new DeferredRowMeans(a, 4, AttributeMap.EMPTY);
DeferredGraph graph = new DeferredGraph(rowMeans);
Vector x = compute(graph);
System.out.println(x);
}