Random noise

Interestingly, the generator itself does not have any source of randomness because it is not a parametric model. The generator is a non-parametric model with fixed coefficients; that is, the coefficients are not sampled from a parametric distribution.

The generator's source of randomness comes from the random noise vector and the generator itself represents a map from this noise vector to some data. The random noise vector is sampled from a known distribution, such as the uniform distribution or the Gaussian distribution.