communication cost formula is wrong

[zishan11]

In quantized scheme:
Original formula in your code: "communication_cost = self.base_bits * self.quant_level + np.ceil(np.log2(len(self.values_update)))"
I sugguest:"communication_cost = self.base_bits * np.log2(self.quant_level)"
In compression scheme:
Your code seems using algo of paper FetchSGD, but it's cost calculation formula is also wrong.