%% ARMA Model with No Constant Term
% This example shows how to specify an ARMA(p, q) model with constant term equal to zero. Use name-value syntax to specify a model that differs from the default model.
% Specify an ARMA(2,1) model with no constant term,
% {y_t} = {\phi _1}{y_{t - 1}} + {\phi _2}{y_{t - 2}} + {\varepsilon _t} + {\theta _1}{\varepsilon _{t - 1}},
% where the innovation distribution is Gaussian with constant variance.

Mdl = arima('ARLags',1:2,'MALags',1,'Constant',0)

% The ArLags and MaLags name-value pair arguments specify the lags corresponding to nonzero AR and MA coefficients, respectively. The property Constant in the created model object is equal to 0, as specified. The model has default values for all other properties, including NaN values as placeholders for the unknown parameters: the AR and MA coefficients, and scalar variance.
% You can modify the created model using dot notation, or input it (along with data) to estimate.
% Copyright 2015 The MathWorks, Inc.