pspm_bf_data.m

function [bf, x] = pspm_bf_data(td)
% ● Description
%   pspm_bf_data provides a generic interface for creating a user-defined
%   response function from a data vector saved in a *.mat file. To use this
%   function, the variables 'datafile' and 'sr' need to be hard-coded. GLM
%   can then be called with the optional argument model.bf = 'pspm_bf_data'.
% ● Format
%   [bf, x] = pspm_bf_data(td)
% ● Arguments
%   td: the time interval in points for sampling
% ● History
%   Introduced in PsPM 5.1.1
%   Written in 2021 by Dominik R Bach (University College London)
%   Maintained in 2022 by Teddy Chao (UCL)

%% Constants
% CHANGE THIS TO CREATE YOUR FUNCTION
datafile = 'pspm_bf_data_sample.mat';
% this should be a *.mat file that contains a variable named 'data' with
% the data vector
sr = 10;
% this should be the sampling rate of your data vector, default to be 10
%% Check input arguments
if nargin==0
  errmsg='No sampling interval stated'; warning('ID:invalid_input', errmsg); return;
end
%% Load data
if isempty(datafile)
  return
end
[~,~,indata,] = pspm_load_data(datafile, 1);
data = indata{1,1}.data;
%% Processing
% determine original sampling points
x_old = - 1/(2*sr) + (1:numel(data))/sr;
% determine new sampling points
x = (td:td:(numel(data)/sr));
% resample
bf = interp1(x_old, data, x, 'nearest', 'extrap');
bf = [0; bf(:)];
x  = [0; x(:)];
return