def _compute_prior_log_p(self, alpha, partition):
log_p = partition.number_of_cells * log(alpha)
for n_c in partition.counts:
log_p += log_gamma(n_c)
n = partition.number_of_items
for i in range(1, n + 1):
log_p -= log_gamma(alpha + i - 1)
return log_p
def _compute_prior_log_p(self, alpha, partition):
log_p = partition.number_of_cells * log(alpha)
for n_c in partition.counts:
log_p += log_gamma(n_c)
n = partition.number_of_items
for i in range(1, n + 1):
log_p -= log_gamma(alpha + i - 1)
return log_p
def log_factorial(n):
return log_gamma(n + 1)
def log_beta(a, b):
if a <= 0 or b <= 0:
return float('-inf')
return log_gamma(a) + log_gamma(b) - log_gamma(a + b)
def log_gamma_pdf(x, a, b):
return -log_gamma(a) + a * log(b) + (a - 1) * log(x) - b * x
def log_beta(a, b):
if a <= 0 or b <= 0:
return -np.inf
return log_gamma(a) + log_gamma(b) - log_gamma(a + b)