ARIMA models

Example

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
import numpy as np
import pandas as pd
from pandas.io.data import DataReader
from datetime import datetime
import pyflux as pf

ibm = DataReader('IBM',  'yahoo', datetime(2000,1,1), datetime(2016,3,10))
ibm['Logged Open'] = np.log(ibm['Open'].values)

model = pf.ARIMA(data=ibm,ar=1,ma=1,integ=1,target='Logged Open')

Class Arguments

class ARIMA(data, ar, ma, integ, target)
data

pd.DataFrame or array-like : the time-series data

ar

int : the number of autoregressive lags

ma

int : the number of moving average lags

integ

int : how many times to difference the time series (default: 0)

target

string (data is DataFrame) or int (data is np.array) : which column to use as the time series. If None, the first column will be chosen as the data.

Class Methods

adjust_prior(index, prior)

Adjusts the priors of the model. index can be an int or a list. prior is a prior object, such as Normal(0,3).

Here is example usage for adjust_prior():

1
2
3
4
5
import pyflux as pf

# model = ... (specify a model)
model.list_priors()
model.adjust_prior(2,pf.Normal(0,1))
fit(method, **kwargs)

Estimates parameters for the model. Returns a Results object. method is an inference/estimation option; see Bayesian Inference and Classical Inference sections for options. If no method is provided then a default will be used.

Optional arguments are specific to the method you choose - see the documentation for these methods for more detail.

Here is example usage for fit():

1
2
3
4
import pyflux as pf

# model = ... (specify a model)
model.fit("M-H",nsims=20000)
plot_fit(**kwargs)

Graphs the fit of the model.

Optional arguments include figsize - the dimensions of the figure to plot.

plot_parameters(indices, figsize)

Returns a plot of the parameters and their associated uncertainty. indices is a list referring to the parameter indices that you want ot plot. Figsize specifies how big the plot will be.

plot_predict(h, past_values, intervals, **kwargs)

Plots predictions of the model. h is an int of how many steps ahead to predict. past_values is an int of how many past values of the series to plot. intervals is a bool on whether to include confidence/credibility intervals or not.

Optional arguments include figsize - the dimensions of the figure to plot.

plot_predict_is(h, past_values, intervals, **kwargs)

Plots in-sample rolling predictions for the model. h is an int of how many previous steps to simulate performance on. past_values is an int of how many past values of the series to plot. intervals is a bool on whether to include confidence/credibility intervals or not.

Optional arguments include figsize - the dimensions of the figure to plot.

predict(h)

Returns DataFrame of model predictions. h is an int of how many steps ahead to predict.

predict_is(h)

Returns DataFrame of in-sample rolling predictions for the model. h is an int of how many previous steps to simulate performance on.