rate going to zero it doesn't really have a gradient flow limit so this is not so nice for the dynamic community of theory so we instead define a slightly different version of stochastic iron descendant we call persistent stochastic variant descent where we as before have some fraction of samples that are in the batch but instead of reshuffling the batch at every time step randomly we actually decide at each time step whether we keep or not the the sample in the batch and we we keep the we keep that sample with some typical time that we call here