docs: public void minus(LinearSparseVector sv) {
  		for (int r = 0; r < sv.length; r++) {
  			int p = Arrays.binarySearch(index, sv.index[r]);
  			if (p >= 0) {
  				data[p] = (float) data[p] - (float) sv.data[r];
  			} else {
  				put(sv.index[r], -(float) sv.data[r]);
  			}
  		}
  	}