docs: public float dotProduct(LinearSparseVector sv, float c) {
  		float product = 0;
  
  		for (int i = 0; i < sv.length; i++) {
  			int p = Arrays.binarySearch(index, sv.index[i]);
  			if (p >= 0) {
  				float val = (float) sv.data[i] + c;
  				val *= (float) data[p];
  				product += val;
  			}
  		}
  
  		return product;
  	}