def _ses_forecast(smoothing_level_constant: float, forecast_demand: Forecast,
forecast_length: int, orders_length: int) -> dict:
""" Private function for executing the simple exponential smoothing forecast.
"""
forecast_breakdown = [
i for i in forecast_demand.simple_exponential_smoothing(
smoothing_level_constant)
]
ape = LinearRegression(forecast_breakdown)
mape = forecast_demand.mean_aboslute_percentage_error_opt(
forecast_breakdown)
stats = ape.least_squared_error()
simple_forecast = forecast_demand.simple_exponential_smoothing_forecast(
forecast=forecast_breakdown, forecast_length=forecast_length)
sum_squared_error = forecast_demand.sum_squared_errors(
simple_forecast, smoothing_level_constant)
standard_error = forecast_demand.standard_error(sum_squared_error,
orders_length,
smoothing_level_constant)
regression_line = _regr_ln(stats=stats)
log.log(
logging.WARNING,
"A STANDARD simple exponential smoothing forecast has been completed.")
return {
'forecast_breakdown': forecast_breakdown,
'mape': mape,
'statistics': stats,
'forecast': simple_forecast,
'alpha': smoothing_level_constant,
'standard_error': standard_error,
'regression': [i for i in regression_line.get('regression')]
}
def test_htces(self):
forecast_demand = Forecast(self.__orders_ex)
ses_forecast = [
i for i in forecast_demand.simple_exponential_smoothing(
*(self.__smoothing_level_constant, ))
]
sum_squared_error = forecast_demand.sum_squared_errors(
ses_forecast, self.__smoothing_level_constant)
standard_error = forecast_demand.standard_error(
sum_squared_error, len(self.__orders_ex),
self.__smoothing_level_constant)
total_orders = 0
for order in self.__orders_ex[:self.__initial_estimate_period]:
total_orders += order
avg_orders = total_orders / self.__initial_estimate_period
evo_mod = OptimiseSmoothingLevelGeneticAlgorithm(
orders=self.__orders_ex,
average_order=avg_orders,
smoothing_level=self.__smoothing_level_constant,
population_size=10,
standard_error=standard_error,
recombination_type='two_point')
ses_evo_forecast = evo_mod.simple_exponential_smoothing_evo(
smoothing_level_constant=self.__smoothing_level_constant,
initial_estimate_period=self.__initial_estimate_period)
self.assertEqual(7, len(ses_evo_forecast))
def test_simple_exponential_smoothing(self):
total_orders = 0
for order in self.__orders_ex[:12]:
total_orders += order
avg_orders = total_orders / 12
f = Forecast(self.__orders_ex, avg_orders)
alpha = [0.2, 0.3, 0.4, 0.5, 0.6]
s = [i for i in f.simple_exponential_smoothing(*alpha)]
sum_squared_error = f.sum_squared_errors(s, 0.5)
self.assertEqual(28447.178137569197, sum_squared_error[0.5])
def test_simple_exponential_smoothing(self):
total_orders = 0
for order in self.__orders_ex[:12]:
total_orders += order
avg_orders = total_orders / 12
f = Forecast(self.__orders_ex, avg_orders)
alpha = [0.2, 0.3, 0.4, 0.5, 0.6]
s = [i for i in f.simple_exponential_smoothing(*alpha)]
sum_squared_error = f.sum_squared_errors(s, 0.5)
self.assertEqual(28447.178137569197, sum_squared_error[0.5])
def test_standard_error(self):
total_orders = 0
for order in self.__orders_ex[:12]:
total_orders += order
avg_orders = total_orders / 12
f = Forecast(self.__orders_ex, avg_orders)
alpha = [0.2, 0.3, 0.4, 0.5, 0.6]
s = [i for i in f.simple_exponential_smoothing(*alpha)]
sum_squared_error = f.sum_squared_errors(s, 0.5)
standard_error = f.standard_error(sum_squared_error, len(self.__orders_ex), 0.5)
self.assertEqual(29, round(standard_error))
def test_standard_error(self):
total_orders = 0
for order in self.__orders_ex[:12]:
total_orders += order
avg_orders = total_orders / 12
f = Forecast(self.__orders_ex, avg_orders)
alpha = [0.2, 0.3, 0.4, 0.5, 0.6]
s = [i for i in f.simple_exponential_smoothing(*alpha)]
sum_squared_error = f.sum_squared_errors(s, 0.5)
standard_error = f.standard_error(sum_squared_error, len(self.__orders_ex), 0.5)
self.assertEqual(29, round(standard_error))
def _run_exponential_smoothing_forecast(self, individual: tuple) -> dict:
f = Forecast(self.__orders, self.__average_order)
simple_expo_smoothing = []
for sm_lvl in individual:
p = [i for i in f.simple_exponential_smoothing(sm_lvl)]
# print(p)
simple_expo_smoothing.append(p)
appraised_individual = {}
for smoothing_level in individual:
sum_squared_error = f.sum_squared_errors_indi(
simple_expo_smoothing, smoothing_level)
standard_error = f.standard_error(sum_squared_error,
len(self.__orders),
smoothing_level)
appraised_individual.update({smoothing_level: standard_error})
# print('The standard error as a trait has been calculated {}'.format(appraised_individual))
return appraised_individual
def test_optimise_smoothing_level_genetic_algorithm(self):
total_orders = 0
for order in self.__orders_ex[:12]:
total_orders += order
avg_orders = total_orders / 12
f = Forecast(self.__orders_ex, avg_orders)
alpha = [0.2, 0.3, 0.4, 0.5, 0.6]
s = [i for i in f.simple_exponential_smoothing(*alpha)]
sum_squared_error = f.sum_squared_errors(s, 0.5)
standard_error = f.standard_error(sum_squared_error, len(self.__orders_ex), 0.5, 2)
evo_mod = OptimiseSmoothingLevelGeneticAlgorithm(orders=self.__orders_ex,
average_order=avg_orders,
smoothing_level=0.5,
population_size=10,
standard_error=standard_error,
recombination_type='single_point')
pop = evo_mod.initial_population()
self.assertGreaterEqual(len(pop), 2)
self.assertNotAlmostEqual(pop[0], 20.72, places=3)
self.assertNotAlmostEqual(pop[1], 0.73, places=3)
def test_optimise_smoothing_level_genetic_algorithm(self):
total_orders = 0
for order in self.__orders_ex[:12]:
total_orders += order
avg_orders = total_orders / 12
f = Forecast(self.__orders_ex, avg_orders)
alpha = [0.2, 0.3, 0.4, 0.5, 0.6]
s = [i for i in f.simple_exponential_smoothing(*alpha)]
sum_squared_error = f.sum_squared_errors(s, 0.5)
standard_error = f.standard_error(sum_squared_error, len(self.__orders_ex), 0.5, 2)
evo_mod = OptimiseSmoothingLevelGeneticAlgorithm(orders=self.__orders_ex,
average_order=avg_orders,
smoothing_level=0.5,
population_size=10,
standard_error=standard_error,
recombination_type='single_point')
pop = evo_mod.initial_population()
self.assertGreaterEqual(len(pop), 2)
self.assertNotAlmostEqual(pop[0], 20.72, places=3)
self.assertNotAlmostEqual(pop[1], 0.73, places=3)
def simple_exponential_smoothing_evo(
self,
smoothing_level_constant: float,
initial_estimate_period: int,
recombination_type: str = 'single_point',
population_size: int = 10,
forecast_length: int = 5) -> dict:
""" Simple exponential smoothing using evolutionary algorithm for optimising smoothing level constant (alpha value)
Args:
initial_estimate_period (int): The number of previous data points required for initial level estimate.
smoothing_level_constant (float): Best guess at smoothing level constant appropriate for forecast.
Returns:
dict:
Example:
"""
log.log(
logging.INFO, "Executing simple exponential smoothing. "
"SMOOTHING_LEVEL: {} "
"INITIAL_ESTIMATE_PERIOD: {} "
"RECOMBINATION_TYPE: {} "
"POPULATION_SIZE: {} "
"FORECAST_LENGTH: {}".format(smoothing_level_constant,
initial_estimate_period,
recombination_type, population_size,
forecast_length))
if None != self.__recombination_type:
recombination_type = self.__recombination_type
sum_orders = 0
for demand in self.__orders[:initial_estimate_period]:
sum_orders += demand
avg_orders = sum_orders / initial_estimate_period
forecast_demand = Forecast(self.__orders, avg_orders)
#calls simple_exponential_smoothing method from Forecast object
ses_forecast = [
i for i in forecast_demand.simple_exponential_smoothing(
*(smoothing_level_constant, ))
]
sum_squared_error = forecast_demand.sum_squared_errors(
ses_forecast, smoothing_level_constant)
standard_error = forecast_demand.standard_error(
sum_squared_error, len(self.__orders), smoothing_level_constant)
evo_mod = OptimiseSmoothingLevelGeneticAlgorithm(
orders=self.__orders,
average_order=avg_orders,
smoothing_level=smoothing_level_constant,
population_size=population_size,
standard_error=standard_error,
recombination_type=recombination_type)
optimal_alpha = evo_mod.initial_population()
optimal_ses_forecast = [
i for i in forecast_demand.simple_exponential_smoothing(
optimal_alpha[1])
]
ape = LinearRegression(optimal_ses_forecast)
mape = forecast_demand.mean_aboslute_percentage_error_opt(
optimal_ses_forecast)
stats = ape.least_squared_error()
simple_forecast = forecast_demand.simple_exponential_smoothing_forecast(
forecast=optimal_ses_forecast, forecast_length=forecast_length)
sum_squared_error = forecast_demand.sum_squared_errors(
optimal_ses_forecast, optimal_alpha[1])
standard_error = forecast_demand.standard_error(
sum_squared_error, len(self.__orders), optimal_alpha[1])
regression = {
'regression': [(stats.get('slope') * i) + stats.get('intercept')
for i in range(0, 12)]
}
log.log(
logging.INFO,
"An OPTIMISED simple exponential smoothing forecast has been completed"
)
return {
'forecast_breakdown': optimal_ses_forecast,
'mape': mape,
'statistics': stats,
'forecast': simple_forecast,
'optimal_alpha': optimal_alpha[1],
'standard_error': standard_error,
'regression': [i for i in regression.get('regression')]
}
def simple_exponential_smoothing_forecast(demand: list = None, smoothing_level_constant: float = 0.5,
forecast_length: int = 5, initial_estimate_period: int = 6, **kwargs) -> dict:
""" Performs a simple exoponential smoothing forecast on
Args:
forecast_length (int): Number of periods to extend the forecast.
demand (list): Original historical demand.
smoothing_level_constant (float): Alpha value
initial_estimate_period (int): Number of period to use to derive an average for the initial estimate.
**ds (pd.DataFrame): Data frame with raw data.
**optimise (bool) Optimisation flag for exponential smoothing forecast.
Returns:
dict: Simple exponential forecast
Examples:
>>> from supplychainpy.model_demand import simple_exponential_smoothing_forecast
>>> orders = [165, 171, 147, 143, 164, 160, 152, 150, 159, 169, 173, 203, 169, 166, 162, 147, 188, 161, 162,
... 169, 185, 188, 200, 229, 189, 218, 185, 199, 210, 193, 211, 208, 216, 218, 264, 304]
>>> ses = simple_exponential_smoothing_forecast(demand=orders, alpha=0.5, forecast_length=6, initial_period=18)
"""
ds = kwargs.get('ds', 'UNKNOWN')
if ds is not UNKNOWN:
orders = list(kwargs.get('ds', "UNKNOWN"))
else:
orders = [int(i) for i in demand]
forecast_demand = Forecast(orders)
# optimise, population_size, genome_length, mutation_probability, recombination_types
if len(kwargs) != 0:
optimise_flag = kwargs.get('optimise', "UNKNOWN")
if optimise_flag is not UNKNOWN:
ses_forecast = [i for i in forecast_demand.simple_exponential_smoothing(*(smoothing_level_constant,))]
sum_squared_error = forecast_demand.sum_squared_errors(ses_forecast, smoothing_level_constant)
standard_error = forecast_demand.standard_error(sum_squared_error, len(orders), smoothing_level_constant)
total_orders = 0
for order in orders[:initial_estimate_period]:
total_orders += order
avg_orders = total_orders / initial_estimate_period
evo_mod = OptimiseSmoothingLevelGeneticAlgorithm(orders=orders,
average_order=avg_orders,
smoothing_level=smoothing_level_constant,
population_size=10,
standard_error=standard_error,
recombination_type='single_point')
ses_evo_forecast = evo_mod.simple_exponential_smoothing_evo(
smoothing_level_constant=smoothing_level_constant,
initial_estimate_period=initial_estimate_period)
return ses_evo_forecast
else:
return _ses_forecast(smoothing_level_constant=smoothing_level_constant,
forecast_demand=forecast_demand,
forecast_length=forecast_length)
else:
return _ses_forecast(smoothing_level_constant=smoothing_level_constant,
forecast_demand=forecast_demand,
forecast_length=forecast_length)
def simple_exponential_smoothing_forecast(
demand: list,
smoothing_level_constant: float = 0.5,
optimise: bool = True,
forecast_length: int = 5,
initial_estimate_period: int = 6,
**kwargs) -> dict:
""" Performs a simple exponential smoothing forecast on historical demand.
Args:
forecast_length (int): Number of periods to extend the forecast.
demand (list): Original historical demand.
smoothing_level_constant (float): Alpha value
initial_estimate_period (int): Number of period to use to derive an average for the initial estimate.
**ds (pd.DataFrame): Data frame with raw data.
**optimise (bool) Optimisation flag for exponential smoothing forecast.
Returns:
dict: Simple exponential forecast
Examples:
>>> from supplychainpy.model_demand import simple_exponential_smoothing_forecast
>>> orders = [165, 171, 147, 143, 164, 160, 152, 150, 159, 169, 173, 203, 169, 166, 162, 147, 188, 161, 162,
... 169, 185, 188, 200, 229, 189, 218, 185, 199, 210, 193, 211, 208, 216, 218, 264, 304]
>>> ses = simple_exponential_smoothing_forecast(demand=orders, alpha=0.5, forecast_length=6, initial_period=18)
"""
try:
ds = kwargs.get('ds', 'UNKNOWN')
if ds is not UNKNOWN:
orders = list(kwargs.get('ds', "UNKNOWN"))
else:
orders = [int(i) for i in demand]
forecast_demand = Forecast(orders)
log.log(logging.INFO, "Started simple exponential smoothing")
# optimise, population_size, genome_length, mutation_probability, recombination_types
if optimise:
log.log(logging.INFO, "Using solver version to find alpha.")
ses_forecast = [
i for i in forecast_demand.simple_exponential_smoothing(
*(smoothing_level_constant, ))
]
sum_squared_error = forecast_demand.sum_squared_errors(
ses_forecast, smoothing_level_constant)
standard_error = forecast_demand.standard_error(
sum_squared_error, len(orders), smoothing_level_constant)
total_orders = 0
for order in orders[:initial_estimate_period]:
total_orders += order
avg_orders = total_orders // initial_estimate_period
evo_mod = OptimiseSmoothingLevelGeneticAlgorithm(
orders=orders,
average_order=avg_orders,
smoothing_level=smoothing_level_constant,
population_size=10,
standard_error=standard_error,
recombination_type='single_point')
ses_evo_forecast = evo_mod.simple_exponential_smoothing_evo(
smoothing_level_constant=smoothing_level_constant,
initial_estimate_period=initial_estimate_period)
return ses_evo_forecast
else:
orders = [int(i) for i in demand]
return _ses_forecast(
smoothing_level_constant=smoothing_level_constant,
forecast_demand=forecast_demand,
forecast_length=forecast_length,
orders_length=len(orders))
except TypeError as e:
if demand is None:
print(
"Please supply a list of demand values. Use the keyword \'demand=\'\n{}"
.format(e))
except OSError as e:
print(e)
