@Override
public void forEachNonZero(final org.apache.mahout.math.function.IntIntDoubleFunction function) {
if (this.isNoView) {
this.elements.forEachPair(
new IntDoubleProcedure() {
@Override
public boolean apply(int key, double value) {
int i = key / columns;
int j = key % columns;
double r = function.apply(i, j, value);