code: public void add(IntFloatVector other) {
          if (other instanceof IntFloatUnsortedVector) {
              IntFloatUnsortedVector vec = (IntFloatUnsortedVector) other;
              for (int i=0; i<vec.top; i++) {
                  this.add(vec.idx[i], vec.vals[i]);
              }
          } else {
              //  TODO: Add special case for IntFloatDenseVector.
              other.iterate(new SparseBinaryOpApplier(this, new Lambda.FloatAdd()));
          }
      }
docs: Updates this vector to be the entrywise sum of this vector with the other.