In Linear's construction, reset_parameter will be called.
    def reset_parameters(self):
        stdv = 1. / math.sqrt(self.weight.size(1))
        self.weight.data.uniform_(-stdv, stdv)
        if self.bias is not None:
            self.bias.data.uniform_(-stdv, stdv)

I think the initialized parameters have a low probability to be all 0s. But the all-zeros output happened frequently. I’ve checked the .grad for net parameter in each loop of iteration when the all-zeros output happen, the result is also all-zeros.