Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_preproc_online_filter_init”.

  function FM = ft_preproc_online_filter_init(B, A, x)
  Initialize an IIR filter model with coefficients B and A, as used in filter and butter etc.
  One sample x of the signal must be given as a column vector.
  This function will calculate the filter delay states such that the initial response
  is as if 'x' would have been applied since forever.