| """File for updating prior into posterior""" | |
| import pymc3 as pm | |
| class PosteriorGenerator: | |
| def __init__(self, prices, demands): | |
| self.price_observations = prices | |
| self.demand_observations = demands | |
| def calc_posterior(self, samples=1000): | |
| with pm.Model(): | |
| elas = pm.Normal("elas",mu=-0.5, sd=0.5) | |
| shape = pm.Normal("shape",mu=0, sd=2) | |
| stdev = pm.Exponential("stdev",lam=1) | |
| y_hat = pm.math.dot(elas, self.price_observations) + shape | |
| log_observations = pm.math.log(self.demand_observations) | |
| _ = pm.Normal("demand", mu=y_hat, observed=log_observations, sigma=stdev) | |
| trace = pm.sample(samples) | |
| return trace | |