def test_standardized_forecasts_error():
"""
Simple test that standardized forecasts errors are calculated correctly.
Just uses a different calculation method on a univariate series.
"""
# Get the dataset
true = results_kalman_filter.uc_uni
data = pd.DataFrame(
true['data'],
index=pd.date_range('1947-01-01', '1995-07-01', freq='QS'),
columns=['GDP']
)
data['lgdp'] = np.log(data['GDP'])
# Fit an ARIMA(1,1,0) to log GDP
mod = SARIMAX(data['lgdp'], order=(1,1,0))
res = mod.fit(disp=-1)
standardized_forecasts_error = (
res.filter_results.forecasts_error[0] /
np.sqrt(res.filter_results.forecasts_error_cov[0,0])
)
assert_allclose(
res.filter_results.standardized_forecasts_error[0],
standardized_forecasts_error,
)
def sarima_model(feature):
data = df1[feature]
values = data.values
values = values.astype('float32')
split = int(len(list(df1["Dollar_eq"])) * 0.8)
#scaled = scale(values,0,1)
train = values[:split]
test = values[split:]
#order=(1, 1, 1), seasonal_order=(1, 1, 1, 1)
model = SARIMAX(train, order=(1, 1, 1), seasonal_order=(1, 1, 1, 1))
model_fit = model.fit(disp=False)
yhat = model_fit.predict(len(train),
len(train) + len(test) - 1,
typ="levels")
x = []
for i in range(len(test)):
x.append((yhat[i], test[i]))
#print(x[0:10])
rmse = sqrt(mean_squared_error(test, yhat))
print("\n\n SARIMA RMSE: %.5f" % rmse)
print()
def sarimax_fc(train,
test,
order,
seas_order,
exog_train=None,
exog_test=None):
model = SARIMAX(train,
order=order,
exog=exog_train,
seasonal_order=seas_order)
results = model.fit()
start, end = len(train), len(test) + len(train) - 1
pred = results.predict(start, end, exog=exog_test,
typ='levels').rename('sarima_predictions')
rmse_pred, rmse_pred_pct = rmse(test, pred), rmse(test, pred) / test.mean()
results = {
'prediction': pred,
'rmse': rmse_pred,
'rmse_pct': rmse_pred_pct
}
return results
def test_small_sample_serial_correlation_test():
# Test the Ljung Box serial correlation test for small samples with df
# adjustment using the Nile dataset. Ljung-Box statistic and p-value
# are compared to R's Arima() and checkresiduals() functions in forecast
# package:
# library(forecast)
# fit <- Arima(y, order=c(1,0,1), include.constant=FALSE)
# checkresiduals(fit, lag=10)
from statsmodels.tsa.statespace.sarimax import SARIMAX
niledata = nile.data.load_pandas().data
niledata.index = pd.date_range('1871-01-01', '1970-01-01', freq='AS')
mod = SARIMAX(endog=niledata['volume'],
order=(1, 0, 1),
trend='n',
freq=niledata.index.freq)
res = mod.fit()
actual = res.test_serial_correlation(method='ljungbox',
lags=10,
df_adjust=True)[0, :, -1]
assert_allclose(actual, [14.116, 0.0788], atol=1e-3)
def sarima_optimizer_aic(train, pdq, seasonal_pdq):
best_aic, best_order, best_seasonal_order = float("inf"), float(
"inf"), None
for param in pdq:
for param_seasonal in seasonal_pdq:
try:
sarimax_model = SARIMAX(train,
order=param,
seasonal_order=param_seasonal)
results = sarimax_model.fit(disp=0)
aic = results.aic
if aic < best_aic:
best_aic, best_order, best_seasonal_order = aic, param,\
param_seasonal
print('SARIMA{}x{}12 - AIC:{}'.format(param, param_seasonal,
aic))
except:
continue
print('SARIMA{}x{}12 - AIC:{}'.format(best_order, best_seasonal_order,
best_aic))
return best_order, best_seasonal_order
def test_dynamic_against_sarimax():
rs = np.random.RandomState(12345678)
e = rs.standard_normal(1001)
y = np.empty(1001)
y[0] = e[0] * np.sqrt(1.0 / (1 - 0.9**2))
for i in range(1, 1001):
y[i] = 0.9 * y[i - 1] + e[i]
smod = SARIMAX(y, order=(1, 0, 0), trend='c')
sres = smod.fit(disp=False)
mod = AutoReg(y, 1, old_names=False)
spred = sres.predict(900, 1100)
pred = mod.predict(sres.params[:2], 900, 1100)
assert_allclose(spred, pred)
spred = sres.predict(900, 1100, dynamic=True)
pred = mod.predict(sres.params[:2], 900, 1100, dynamic=True)
assert_allclose(spred, pred)
spred = sres.predict(900, 1100, dynamic=50)
pred = mod.predict(sres.params[:2], 900, 1100, dynamic=50)
assert_allclose(spred, pred)
def sarimax_forecast(df):
'''it takes a dataframe split it into train/forecast sets based on
the availability of price and then forecasts electricity price for next hour.
it returns forecast dataframe ('price','lower_interval', 'upper_interval') and
historical price dataframe ('price')'''
# split past and furture
past = df[~df.price.isnull()]
future = df[df.price.isnull()].drop('price', axis=1)
# forecast for next time point only
future = future.iloc[:1, :]
if future.temp.isnull(
)[0]: # when weather forecast data is not available for that hour
forecast = np.nan
lower = np.nan
upper = np.nan
print('weather data is not available')
else:
past.index = pd.DatetimeIndex(past.index.values,
freq=past.index.inferred_freq)
# Build Model
sarima = SARIMAX(past.price,
exog=past.drop('price', axis=1),
order=(1, 1, 1),
seasonal_order=(1, 0, 2, 7))
sarima = sarima.fit(maxiter=300)
# forecasting
results = sarima.get_forecast(1, exog=future, alpha=0.05)
forecast = sarima.forecast(1, exog=future, alpha=0.05)
lower = results.conf_int()['lower price'][0]
upper = results.conf_int()['upper price'][0]
# create forecast df with datetimeIndex
forecast = pd.DataFrame(dict(price=forecast,
lower_interval=lower,
upper_interval=upper),
index=future.index)
forecast.index.name = 'date_time'
past = past.iloc[-1:, 0]
return forecast, past
def SARIMA_forecast(experiment, plot_fit=False):
"""
Fit SARIMA model on L_train data and forecast N_test steps ahead
Args:
experiment(dict): Experiment dictionary.
Returns:
experiment(dict): Experiment dictionary with additional keys.
"""
L_train = experiment['L_train']
N_train = experiment['N_train']
N_test = experiment['N_test']
# Fit SARIMA model
model = SARIMAX(L_train,
order=(1, 1, 1),
seasonal_order=(1, 1, 0, 24),
enforce_invertibility=False,
enforce_stationarity=False)
model_fit = model.fit(disp=False)
L_train_prediction = model_fit.fittedvalues
L_test_prediction = model_fit.forecast(steps=N_test)
# reshape arrays
L_test_prediction = L_test_prediction.reshape((N_test, 1))
L_train_prediction = L_train_prediction.reshape((N_train, 1))
# plot fit on training data and prediction
if plot_fit:
plt.figure()
plt.plot(L_train)
plt.plot(L_train_prediction, 'red')
plt.figure()
plt.plot(L_test_prediction, 'red')
experiment['L_test_prediction'] = L_test_prediction
experiment['L_train_prediction'] = L_train_prediction
return experiment
def SARIMA(self,
idx,
numpredictions,
order=(0, 1, 1),
seasonal_order=(0, 1, 1, 24),
trend=None):
# use every hour to gain the parameters
nDays = 7 * 4
trainingData = self.dataX[max(idx - nDays * 24, 0):idx,
cfg.prediction['pos']]
model = SARIMAX(trainingData,
order=order,
trend=trend,
seasonal_order=seasonal_order,
enforce_stationarity=False,
enforce_invertibility=False)
with warnings.catch_warnings():
warnings.filterwarnings("ignore")
self.trained_model = model.fit(disp=False)
pred = self.trained_model.forecast(cfg.prediction['num_predictions'])
return pred
def SeasonaAutoIntegratedMovingAverageExogenousRegressors(
self, data, exodata):
#currently, exodata not used.
#make a dataframe the size of prediction
datahat = pd.DataFrame(np.zeros(shape=((self.end - self.start), 3)))
# create a model for each axis and predict each axis
for i in range(3):
# make prediction
x = data[i].values.tolist() #get the col values to be a list
x1 = exodata[i].values.tolist()
model = SARIMAX(x,
exog=x1,
order=(1, 1, 1),
seasonal_order=(0, 0, 0, 0))
model_fit = model.fit(disp=False)
datahat.iloc[:,
i] = model_fit.predict(self.start,
self.end - 1,
exog=[exodata]) #not sure here
return (datahat)
def forcast(i):
sarima_model = SARIMAX(train, order=(1,0,1), seasonal_order=(0,1,1,2), enforce_stationarity=False, enforce_invertibility=False)
sfit = sarima_model.fit()
print(sfit.summary())
sfit.plot_diagnostics(figsize=(10, 6))
plt.show()
#print(sarima_model.summary())
#dati di predicton non di forcast ancora detto prediction in sample
ypred=sfit.predict(start=0,end=len(train))
plt.plot(train)
plt.plot(ypred)
plt.title("trian")
#previsione de dati quindi il forcat --->il modelo è stato esteso al futuro
forewrap = sfit.get_forecast(steps=523)
forecast_ci = forewrap.conf_int()
forecast_val = forewrap.predicted_mean
#forecast_val=forecast_val[1:]
plt.plot(train)
#plt.fill_between(forecast_ci.index,forecast_ci.iloc[:, 0],forecast_ci.iloc[:, 1], color='k', alpha=.25)
plt.plot(forecast_val)
plt.plot(test)
plt.show()
yfore = []
for j in range(0, horizon_data_length):
print("Actual {} {} {:.2f} forcast {:.2f}".format(i, j, test[j], forecast_val[j]))
yfore.append(forecast_val[j])
metrics = forecast_accuracy(forecast_val, test)
print("RMSE is {}={:.2f} forecast{:.2f}".format(i ,metrics['rmse']))
return yfore, horizon_data_length
def sarimaxPrdict(train_y,
p_order,
p_seasonal_order,
vtrend,
steps=1,
disp=False):
model = SARIMAX(train_y,
order=p_order,
seasonal_order=p_seasonal_order,
trend=vtrend,
enforce_stationarity=False,
enforce_invertibility=False)
model_fit = model.fit(disp=False)
pred = model_fit.forecast(steps=steps)
if disp:
pred_ci = pd.DataFrame(index=pred.index)
pred_ci['low'] = pred - pred * 0.05
pred_ci['upper'] = pred + pred * 0.05
#pred_ci.loc[y.index[-1]]=[y[-1],y[-1]]
#pred_ci=pred_ci.sort_index()
ax = train_y['2018':].plot(label='observed')
pred.plot(ax=ax, label='Forecast', alpha=.7)
ax.fill_between(pred.index,
pred_ci.iloc[:, 0],
pred_ci.iloc[:, 1],
color='k',
alpha=.1)
ax.set_xlabel('Date')
ax.set_ylabel(train_y.name)
plt.legend()
plt.show()
return pred
def sarima_orders(ts):
p = q = d = range(0, 2)
pdq = list(itertools.product(p, d, q))
seasonal_pdq = [(x[0], x[1], x[2], 12)
for x in list(itertools.product(p, d, q))]
print('SARIMA parameters...')
for param in pdq:
for param_seasonal in seasonal_pdq:
try:
mod = SARIMAX(ts,
order=param,
seasonal_order=param_seasonal,
enforce_stationarity=False,
enforce_invertibility=False)
results = mod.fit()
print('ARIMA{}x{} - AIC:{}'.format(param, param_seasonal,
results.aic))
except:
print('hello')
continue
def modifyFile(reader, writer, count):
global dateToModify, index
while (True):
clas, data, label = getData(reader, count)
if (clas == 0):
break
data0 = pd.Series(label)
data0.index = pd.Index(index)
try:
model = SARIMAX(data0, order=(1,1,1), seasonal_order=(0,1,1,7))
result = model.fit()
except:
print("%d: failed to train sarimax model, abort" % clas)
for i in range(0, count):
writer.writerow(data[i] + [label[i]])
continue
for i in dateToModify:
label[i] = round(result.predict(i, i)[0])
if (label[i] < 0):
label[i] = 0
for i in range(0, count):
writer.writerow(data[i] + [label[i]])
def GridSearch(self, n_days):
self.Build_Training_Data(v=n_days, training=True)
warnings.filterwarnings("ignore")
params = []
scores = []
for p in range(1, 5):
for q in range(1, 5):
for d in range(3):
try:
model = SARIMAX(self.Values,
order=(p, d, q),
missing='drop',
enforce_invertibility=False)
results = model.fit(disp=0)
scores_counties = []
for county in self.Counties:
DataCounty = self.Data_Dates[county].dropna()
ModelCounty = SARIMAX(DataCounty[:-self.v],
order=(p, d, q),
missing='drop',
enforce_invertibility=False)
res = ModelCounty.smooth(results.params)
fc = res.get_prediction(
len(DataCounty) - self.v, len(DataCounty))
frame = fc.summary_frame(alpha=0.05)
fc = frame['mean']
Y = DataCounty.iloc[-self.v:].values
Yhat = fc[-self.v:].values
# Ybar = np.mean(Y)
MAE = (sum(abs(Y - Yhat)) / self.v)
scores_counties.append(MAE)
except:
print('Training failed for parameters :', (p, d, q))
scores.append(np.nanmean(scores_counties))
params.append((p, d, q))
argbest = np.argmin(scores)
print('Best MAE : ', scores[argbest])
print('Best params : ', params[argbest])
self.BestParams = params[argbest]
def arima_grid_search(dataframe, s):
p = d = q = range(2)
param_combinations = list(itertools.product(p, d, q))
lowest_aic, pdq, pdqs = None, None, None
total_iterations = 0
for order in param_combinations:
for (p, q, d) in param_combinations:
seasonal_order = (p, q, d, s)
total_iterations += 1
model = SARIMAX(data,
order=order,
seasonal_order=seasonal_order,
enforce_stationarity=False,
enforce_invertibility=False,
disp=False,
simple_differencing=False)
model_result = model.fit(maxiter=500, disp=False)
if not lowest_aic or model_result.aic < lowest_aic:
lowest_aic = model_result.aic
ret = model_result
return ret
def PrintParameterMatrix(self, dataset, maxNonSeasonal, maxSeasonal,
lagsPerDay, noTrainingDays):
max_p = maxNonSeasonal[0]
max_d = maxNonSeasonal[1]
max_q = maxNonSeasonal[2]
max_P = maxSeasonal[0]
max_D = maxSeasonal[1]
max_Q = maxSeasonal[2]
aic = list()
bic = list()
orders = list()
train_set = dataset[-noTrainingDays * int(lagsPerDay):-int(lagsPerDay)]
for P, D, Q in itertools.product(range(0, max_P + 1),
range(0, max_D + 1),
range(0, max_Q + 1)):
for p, d, q in itertools.product(range(0, max_p + 1),
range(0, max_d + 1),
range(0, max_q + 1)):
if P == 0 and D == 0 and Q == 0 and p == 0 and d == 0 and q == 0:
continue
try:
model = SARIMAX(train_set,
order=(p, d, q),
seasonal_order=(P, D, Q, int(lagsPerDay)))
result = model.fit()
order = 'Model: Nonseanonal ('+ repr(p) +','+repr(d)+','+ repr(q) + ') Seasonal: '+\
'(' + repr(P) +',' + repr(D) +','+repr(Q) + ')'
print(order)
print(result.summary())
orders.append(order)
bic.append(result.bic)
aic.append(result.aic)
except Exception as e:
print(e)
results = pd.DataFrame(index=orders, data={'aic': aic, 'bic': bic})
print(results)
def SARIMA_GridSearch(self, idx, numpredictions):
nDays = 7
trainingData = self.dataX[(idx - (nDays * 24) - 1):(idx),
cfg.prediction['pos']]
cfg_list = sarima_configs(seasonal=[24])
# do the grid search on the training data
with warnings.catch_warnings():
warnings.filterwarnings("ignore")
#scores = grid_search(trainingData, cfg_list, cfg.prediction['num_predictions'], parallel=False)
scores = grid_search(trainingData, cfg_list, 1, parallel=True)
err = list()
for i, data in enumerate(scores):
err.append(data[1])
index = err.index(min(err))
# train the modell with the last 7 days and predict
trainingData = self.dataX[max(idx - nDays * 24, 0):(idx),
cfg.prediction['pos']]
order = cfg_list[index][0]
season_order = cfg_list[index][1]
trend = cfg_list[index][2]
#print('order = ', order)
#print('season_order = ', season_order)
#print('season_order = ', trend)
model = SARIMAX(trainingData,
order=order,
seasonal_order=season_order,
trend=trend,
enforce_invertibility=False,
enforce_stationarity=False)
with warnings.catch_warnings():
warnings.filterwarnings("ignore")
self.trained_model = model.fit(disp=False)
pred = self.trained_model.forecast(cfg.prediction['num_predictions'])
return pred
def show_bestScore(train_set, test_set):
"""
Returns best cross-validated
MAE and (p,d,q) order
for a ts model.
"""
start = input("Do you have p, d and q values defined? ")
if start == "No" or start == "no" or start == "N" or start == "n":
print("Please define p, d, q values and retry.")
else:
print("Finding out...")
target = [values for values in train_set]
testVals = [values for values in test_set]
target = train_set.astype("float32")
testVals = test_set.astype("float32")
score = [10000, (0, 0, 0)]
for p in pList:
for d in dList:
for q in qList:
order = (p, d, q)
model = SARIMAX(target, order=order)
fit = model.fit(disp=False)
preds = fit.forecast(len(test_set))
error = mean_absolute_error(testVals, preds)
if score[0] != 0 and error < score[0]:
score.pop()
score.pop()
score.append(error)
score.append(order)
best_score, best_order = score[0], score[1]
out = print("Best SARIMAX: MAE = %.f :: Order = %s" %
(best_score, best_order))
if not best_score:
print("Invalid or missing value for MAE. Please retry.")
elif not best_order:
print("Invalid or missing order of values. Please retry.")
else:
return out # Best MAE = 700 :: Order = (8, 3, 1)
def train_SARIMA_model(self, df, game_id, dep_var, indep_var, target, type,
model_type):
Y = df[dep_var]
X = df[indep_var]
if len(Y) <= 24 and not self.seasonal_order is None:
print("Length of dependent variable is to short: {}".format(len(Y)))
return
if len(X) <= 24 and not self.seasonal_order is None:
print("Length of dependent variables is to short: {}".format(len(X)))
return
if self.seasonal_order is None:
model = SARIMAX(endog=Y, exog=X, order=self.order, enforce_stationarity=False, enforce_invertibility=False)
else:
model = SARIMAX(endog=Y, exog=X, order=self.order, seasonal_order=self.seasonal_order, enforce_stationarity=False, enforce_invertibility=False)
fitted_model = model.fit()
# print(fitted_model.summary())
save_path = util.build_model_save_path(game_id, target, type, model_type)
fitted_model.save(save_path, remove_data=True)
def forecast(data):
"""
Function to predict the next 7 values for the input data using SARIMAX
Auto regression function
Returns: A list of predictions for next 7 days
"""
predictions = []
for i in range(7):
# Initializing the model
model = SARIMAX(data,
order=(1, 1, 1),
trace=True,
error_action="ignore")
# Fitting the model
model_fit = model.fit(disp=False)
# Predicting the values one by one
yhat = model_fit.predict(len(data), len(data))
data.append(int(yhat))
# Appending each prediction to a list
predictions.append(int(yhat))
return predictions
def sarimax_forecast(hour=11):
'''hour: hour of a day, range(0, 23),
returns forecast, upper_intervals, lower_intervals, mape, mase, test, train'''
df_all = get_data(hour=hour)
# split past and furture
past = df_all[~df_all.price.isnull()]
future = df_all[df_all.price.isnull()].drop('price', axis=1)
future = future.iloc[:1, :]
if future.temp.isnull()[0]:
forecast = np.array([np.nan])
confidence_int = pd.DataFrame(
{
'lower price': np.nan,
'upper price': np.nan
}, index=['x'])
else:
past.index = pd.DatetimeIndex(past.index.values,
freq=past.index.inferred_freq)
# Build Model
sarima = SARIMAX(past.price,
past.drop('price', axis=1),
order=(1, 1, 1),
seasonal_order=(1, 0, 2, 7))
sarima = sarima.fit(maxiter=300)
# forecasting
results = sarima.get_forecast(1, exog=future, alpha=0.05)
forecast = sarima.forecast(1, exog=future, alpha=0.05)
confidence_int = results.conf_int()
# create forecast df with datetimeIndex
lower = confidence_int['lower price'][0]
upper = confidence_int['upper price'][0]
forecast = pd.DataFrame(dict(price=forecast, lower=lower, upper=upper),
index=future.index)
past = past.iloc[-1:, 0]
return forecast, past
def sarima_forecast(history, config):
order, sorder, trend = config
# define model
blockPrint()
model = SARIMAX(history,
order=order,
seasonal_order=sorder,
trend=trend,
enforce_stationarity=False,
enforce_invertibility=False)
# fit model
t0 = time.time()
model_fit = model.fit(disp=False)
train_time = time.time() - t0
#make one step forecast
t0 = time.time()
yhat = model_fit.predict(len(history), len(history))
predi_time = time.time() - t0
enablePrint()
return yhat[0], train_time, predi_time
def train_sarima_model(y_train,
order,
seasonal_order,
plot_diagnostics=True,
**kwargs):
"""Trains a SARIMAX model based on the training data, y_train,
SARIMA parameters, order and seasonal_order, and other keywords.
Will also return a diagnostics plot of the model if plot_diagnostics=True."""
# Fit Model
model = SARIMAX(y_train,
order=order,
seasonal_order=seasonal_order,
**kwargs)
results = model.fit()
# Plot diagnostics, if true
if plot_diagnostics:
results.plot_diagnostics(figsize=(15, 8))
plt.show()
return results
def SARIMAX_forecast(series, cfg, pred_len):
"""DOCSTRING"""
X = series
# set trainset to include all but last 48 months (4 years)
# only training on data between 9-4 years ago
train_size = int(len(X) - pred_len)
train, test = X[0:train_size], X[train_size:]
model = SARIMAX(train,
order=cfg[0],
seasonal_order=cfg[1],
trend=cfg[2],
initialization='approximate_diffuse')
results = model.fit()
# Predict 48 months from end of train set
forecast = results.predict(start=test.index[0], end=test.index[-1])
return forecast
def make_arimax_model_with_params(param_dict, time_series, train_fraction, exog_var):
'''
This function takes a dictionary of parameters and parameter values and makes a SARIMA model with those parameters.
It then splits a time series into a train section and a test section. It fits the model on the train time series, then returns the fitted model, the train time series, and the test time series.
It expects a parameter dictionary of the following format:
param_dict = {'order': (p, d, q), 'seasonal': (p, d, q, m), 'trend': 'c' or 't' or 'n' or 'ct', 'enforce_stationarity': True or False, 'enforce_invertibility': True or False }
It returns the fitted model (result), time_series_train, and time_series_test.
If there are exogenous variables, it will return the fitted model, time_series_train, time_series_test, exog_series_train, and exog_series_test.
'''
warnings.filterwarnings("ignore")
order_params = param_dict['order']
seasonal_params = param_dict['seasonal']
trend_param = param_dict['trend']
stationarity_param = param_dict['enforce_stationarity']
invertibility_param = param_dict['enforce_invertibility']
time_series_length = len(time_series)
time_series_train = time_series[0:math.ceil(train_fraction*time_series_length)]
time_series_test = time_series[math.ceil(train_fraction*time_series_length):]
if exog_var is None:
exog_series_train = None
exog_series_test = None
else:
exog_series_train = exog_var[0:math.ceil(train_fraction*time_series_length)]
exog_series_test = exog_var[math.ceil(train_fraction*time_series_length):]
model = SARIMAX(time_series_train, exog=exog_series_train, order=order_params, seasonal_order=seasonal_params, trend=trend_param, enforce_stationarity=stationarity_param, enforce_invertibility=invertibility_param)
result = model.fit(display=0)
if exog_var is None:
return result, time_series_train, time_series_test, None, None
else:
return result, time_series_train, time_series_test, exog_series_train, exog_series_test
def predictTemperature2(startDate, endDate, temperature, n) -> list:
if len(temperature) != 24:
raise ValueError('temperature must be an array with 24 elements')
start_date = datetime.strptime(startDate, "%Y-%m-%d")
end_date = datetime.strptime(endDate, "%Y-%m-%d") + timedelta(hours=23)
artificial_days = 10
artificial_start = start_date - timedelta(days=artificial_days)
date_list = [
artificial_start + timedelta(hours=x)
for x in range(((end_date - artificial_start).days + 1) * 24)
]
# There is too little data (1 day) and we want to predict many days so we are going to create several
# days worth of data prior to the true data, based on the existing data with a +- randomization
rdm_temp = np.random.choice(range(-20, 20, 1), artificial_days * 24) / 10
full_temp = np.concatenate(
[rdm_temp + temperature * artificial_days, temperature])
# Group in dataframe
df = pd.DataFrame.from_dict({
'date': date_list,
'temp': full_temp
}).set_index('date')
sarima_model = SARIMAX(df,
order=(1, 1, 1),
seasonal_order=(1, 1, 1, 24),
enforce_invertibility=False,
enforce_stationarity=True,
initialization='approximate_diffuse')
sarima_fit = sarima_model.fit()
new_data_points = [(date_list[-1] + timedelta(days=k)).strftime("%Y-%m-%d")
for k in [1, n + 1]]
sarima_pred = sarima_fit.get_prediction(*new_data_points)
# Filter last value of the next day
results = sarima_pred.prediction_results._forecasts[0][:-1]
return results
def sarimax_cv(df):
p = range(0, 4)
d = range(0, 2)
q = range(0, 2)
s = [6, 12]
# Generate all different combinations of p, q and q triplets
pdq = list(itertools.product(p, d, q))
# Generate all different combinations of seasonal p, q and q triplets
seasonal_pdq = [(x[0], x[1], x[2], x[3])
for x in list(itertools.product(p, d, q, s))]
#reformatting the data for use in SARIMAX model
sorted_df = df[['Month_Year', 'Eviction_Notice'
]].groupby('Month_Year').sum().reset_index()
sorted_df['Eviction_Notice'] = sorted_df['Eviction_Notice'].astype(float)
y = sorted_df[['Month_Year', 'Eviction_Notice']].set_index(['Month_Year'],
inplace=False)
results = 40000000
pdq_best = None
seasonal_best = None
for param in pdq:
for param_seasonal in seasonal_pdq:
try:
mod = SARIMAX(y,order=param, seasonal_order=param_seasonal,\
enforce_stationarity=False, enforce_invertibility=False)
results = mod.fit()
if results.aic < results:
results = results.aic
pdq_best = param
seasonal_best = param_seasonal
except:
continue
return results, pdq_best, seasonal_best
def sarima(n_input, n_preds, df):
# To get which SARIMA model to use
"""
auto_arima(df['Value'], m=12).summary()
-> SARIMAX(1, 1, 2)x(2, 1, 2, 12)
"""
train, test, _, _, inputs, _ = train_test_split(n_preds, df)
model = SARIMAX(train['Value'],
order=(1, 1, 2),
seasonal_order=(2, 1, 2, 12))
results = model.fit()
start = len(train)
end = len(train) + len(test) - 1
predictions = results.predict(start=start,
end=end,
dynamic=False,
typ='levels')
predictions = predictions.tolist()
return test, 'SARIMA ({}, {})'.format(n_input, n_preds), predictions
def modelEvaluated(data, sarimaOrder):
#training data will be 8 years or 96 data points
t = floor(len(data) * 0.8)
x_train, x_test = data[0:t], data[t:]
history = [x for x in x_train]
#predictions
predictions = list()
order, sorder, trend = sarimaOrder
for i in range(len(x_test)):
model = SARIMAX(history,
order=order,
seasonal_order=sorder,
trend=trend,
simple_differencing=True,
enforce_stationarity=False,
enforce_invertibility=False)
model_fit = model.fit(disp=False)
y_hat = model_fit.forecast()[0]
predictions.append(y_hat)
history.append(x_test[i])
#out-of-sample error
error = mean_squared_error(x_test, predictions)
return sqrt(error)
def sarima_forecast(history, config):
order, sorder, trend = config
# 定义模型
# order是普通参数，seasonal_order是季节参数，trend是趋势类型
# 该实现称为SARIMAX而不是SARIMA，因为方法名称的"X"表示该实现还支持外生变量。
# 外生变量是并行时间序列变量，不是直接通过AR，I或MA流程建模的，而是作为模型的加权输入提供的。
# 外生变量是可选的，可以通过"exog"参数指定，SARIMAX(data, exog=other_data,...)
model = SARIMAX(history,
order=order,
seasonal_order=sorder,
trend=trend,
enforce_stationarity=False,
enforce_invertibility=False)
# 训练模型过程中会有很多调试信息，disp=0或disp=False表示关闭信息
model_fit = model.fit(disp=False)
# 进行预测，有forecast(n)和predict(start,end)两种预测方法，foreast预测是对样本外的数据进行预测，predict可以对样本内和样本外的进行预测：
# forecast(n)对于输入的训练数据history，每次向后预测n个数值，不写n时默认预测一个值
# predict(start,end)表示预测从输入训练样本的第一个值开始计数，预测第start到第end个数据。输入5条训练数据，predict(8,9)表示预测第9~10条数据(样本外)，predict(3,6)表示预测第4~7条数据(样本内)
#yhat = model_fit.forecast()
#yhat = model_fit.predict(start=len(history),end=len(history))，start和end可以省略
yhat = model_fit.predict(len(history), len(history))
# 返回预测数组中的第一条数据
return yhat[0]
