def test_normal_variable(self):
# to avoid static method warnings in tests,
# that by construction of the unittest package have to be expressed in such way
self.dummy_variable = "dummy_value"
mu = 53
sigma = 4
tol = 0.15
norm = Normal(mu=mu, sigma=sigma)
values = norm.get_values(no_values=400)
rand = RandomVariable()
rand.calculate_parameters(values)
if not rand.get_distribution_type() == "NORMAL":
raise Exception("Excepted a normal!")
mu_r = rand.random_variable.mu
sigma_r = rand.random_variable.sigma
diff_value_mu = abs(mu - mu_r) / (max(abs(mu), abs(mu_r)))
diff_value_sigma = abs(sigma - sigma_r) / (max(abs(sigma), abs(sigma_r)))
if diff_value_mu > tol or diff_value_sigma > tol:
raise Exception("parameters found outside tolerance")
def read_from_string(self, distribution_type, distribution_parameters):
"""
Read the random variable from string
Parameters
-----------
distribution_type
Distribution type
distribution_parameters
Distribution parameters splitted by ;
"""
if distribution_type == "NORMAL":
self.random_variable = Normal()
self.random_variable.read_from_string(distribution_parameters)
elif distribution_type == "UNIFORM":
self.random_variable = Uniform()
self.random_variable.read_from_string(distribution_parameters)
elif distribution_type == "EXPONENTIAL":
self.random_variable = Exponential()
self.random_variable.read_from_string(distribution_parameters)
elif distribution_type == "IMMEDIATE":
self.random_variable = Constant0()
def calculate_parameters(self,
values,
parameters=None,
force_distribution=None):
"""
Calculate parameters of the current distribution
Parameters
-----------
values
Empirical values to work on
parameters
Possible parameters of the algorithm
force_distribution
If provided, distribution to force usage (e.g. EXPONENTIAL)
"""
if parameters is None:
parameters = {}
debug_mode = parameters["debug"] if "debug" in parameters else False
if self.random_variable is not None:
self.random_variable.calculate_parameters(values)
else:
norm = Normal()
unif = Uniform()
expon = Exponential()
constant = Constant0()
if not force_distribution or not force_distribution == "EXPONENTIAL":
likelihoods = list()
likelihoods.append(
[constant,
constant.calculate_loglikelihood(values)])
if force_distribution == "NORMAL" or force_distribution is None:
norm.calculate_parameters(values)
likelihoods.append(
[norm, norm.calculate_loglikelihood(values)])
if force_distribution == "UNIFORM" or force_distribution is None:
unif.calculate_parameters(values)
likelihoods.append(
[unif, unif.calculate_loglikelihood(values)])
if force_distribution == "EXPONENTIAL" or force_distribution is None:
expon.calculate_parameters(values)
likelihoods.append(
[expon, expon.calculate_loglikelihood(values)])
likelihoods = [x for x in likelihoods if str(x[1]) != 'nan']
likelihoods = sorted(likelihoods,
key=lambda x: x[1],
reverse=True)
if debug_mode:
print("likelihoods = ", likelihoods)
self.random_variable = likelihoods[0][0]
else:
avg_values = np.average(values)
if values and avg_values > 0.00000:
expon.scale = avg_values
self.random_variable = expon
else:
self.random_variable = constant