R/model.R

In nxskok/poistan: Fit Poisson model to goal-scoring data via Stan

#' Obtain compiled model
#' 
#' Get object containing compiled Stan model
#' 
#' @param None.
#'   
#' @return Stan model object for passing into model-fitting and model-describing
#'   functions.
#' @export
compiled_model=function()
{
  # home advantage added
  model='
  data
{
  int<lower=1> ng;
  int<lower=1> nt;
  int x[ng,2];
  int y[ng,2];
}
  
  parameters
{
  real o[nt];
  real d[nt];
  real h;
}
  
  model
{
  int t1;
  int t2;
  real eta1;
  real eta2;
  real nu1;
  real nu2;
  o~normal(0,3);
  d~normal(0,3);
  h~normal(0,3);
  for (i in 1:ng)
{ 
  t1<-x[i,1];
  t2<-x[i,2];
  nu1<-h+o[t1]-d[t2];
  nu2<-o[t2]-d[t1];
  eta1<-exp(nu1);
  eta2<-exp(nu2);
  y[i,1]~poisson(eta1);
  y[i,2]~poisson(eta2);
}
}  
  '
  rstan::stan_model(model_code=model)
}