Returns perplexity for each model in a celdaList as calculated by `perplexity().`
celdaPerplexity(celdaList)List. Contains one celdaModel object for each of the parameters specified in the `runParams()` of the provided celda list.
data(celdaCGGridSearchRes)
celdaCGGridModelPerplexities <- celdaPerplexity(celdaCGGridSearchRes)