Memory capacity and information capacity of sparsely encoded associative memory with replacement units

We introduce sparse encoding into the autoassociative memory model with replacement units. Utilizing computer simulation, we search the optimal number of replacement units in two terms: the memory capacity and the information capacity of the network. We show that the optimal number of replacement units to maximize the memory capacity and the information capacity decreases as the firing ratio decreases, and that the difference in the memory capacity between sparse encoding and non-sparse encoding becomes small as the number of replacement units increases.