code: public SparseVector scale(double alpha) {
  		SparseVector a = this;
  		SparseVector c = new SparseVector(N);
  		for (int i : a.symbolTable) c.put(i, alpha * a.get(i));
  		return c;
  	}
docs: Calculates  alpha * a
  
  @param alpha
  @return