@Override
public double get(int row, int col) {
if (row == col) {
return diag.get(row);
}
return -backing.get(row, col);
}
@Override
// todo: update to use vector ops
public void multAdd(double alpha, double[] x, double[] y) {
int l = backing.numRows();
for (int i = 0; i < l; i++) {
y[i] = -y[i];
}
backing.multAdd(x, y);
for (int i = 0; i < l; i++) {
y[i] = diag.get(i) * x[i] - y[i];
}
}