MultinomFourier - p-Values of Multinomial Goodness-of-Fit Tests by Fourier Series Inversion

Computes p-values of multinomial goodness-of-fit tests based on an additive statistic: the log-likelihood ratio, Pearson's chi-squared, the Cressie-Read power divergence, and the exact multinomial test. The main function, pval_fourier(), writes the p-value as a Fourier series in the moment-generating function of the statistic and sums it until an adaptive stopping rule is met, which makes small p-values of large instances computationally feasible. The function pval_exact() computes the exact p-value by branch pruning with bounds from a dynamic program, and pval_flexible() chooses between the two according to the size of the instance.