univariate_distributions/beta_function_tests.R at master · hexhead/univariate_distributions · GitHub

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# beta_function_tests.R - Bill White - 2/1/19

source("beta_function.R")

# ----------------------------------------------------------------------------
n <- 9
z <- seq(from = 0, to = 1, by = 0.01)
alphas <- c(0.5, 5, 1, 2, 2)
betas <- c(0.5, 1, 3, 2, 5)

plot_lists <- lapply(seq_len(length(alphas)), function(param_idx) {
  unlist(lapply(z, function(z_i) {
    #amstat_beta_binomial(z_i, n, alphas[param_idx], betas[param_idx])
    amstat_beta_pdf(z_i, alphas[param_idx], betas[param_idx])
  }))
})

series_labels <- c(paste('params', seq_len(length(alphas)), sep = ""))
series_colors <- rainbow(length(alphas))
series_pchs <- rep(16, length(alphas))
series_types <- rep('l', length(alphas))

x_vals <- seq_along(plot_lists[[1]])
plot(x_vals, plot_lists[[1]],
     xlab = 'Domain Values x (0, 1)',
     ylab = 'Beta Distribution Value for Input x',
     ylim = c(0, 3),
     main = 'Beta\nProbability Density Function',
     type = series_types[1], pch = series_pchs[1], col = series_colors[1])
legend("topright", title = "alpha, beta",
       legend = unlist(lapply(seq_len(length(alphas)), FUN = function(idx) {
         sprintf("%3.1f, %3.1f", alphas[idx], betas[idx])
       })),
       col = series_colors,
       pch = series_pchs)
points(x_vals, plot_lists[[2]],
       type = series_types[2],
       pch = series_pchs[2],
       col = series_colors[2])
points(x_vals, plot_lists[[3]],
       type = series_types[3],
       pch = series_pchs[3],
       col = series_colors[3])
points(x_vals, plot_lists[[4]],
       type = series_types[4],
       pch = series_pchs[4],
       col = series_colors[4])