function [ data ] = pnImputeField(data, field)
%PNIMPUTEFEATURE Impute a feature into the data cell
% [ stat ] = pnImputeFeature(data)
%
% Inputs:
% data - Cell array of data.
% Column 1 - Subject IDs
% Column 2 - Time stamp vectors for each subject
% Column 3 - Feature name vectors for each subject
% Column 4 - Data value vectors for each subject
%
% field - Cell array of identical format to data. However,
% there should only be one type of feature.
%
% Outputs:
% data - Cell array of data with feature imputed at the correct
% time locations.
%
% Example
% bpath = './set-a/';
% data = pnLoadTextFilesCell(bpath);
% field = pnBodySurface(data);
% data = pnImputeField(data,field);
%
% See also PNEXTRACTFIELD PNGENERATEFEATURES
% References:
% Physionet Challenge 2012
% Copyright 2012 Alistair Johnson
% $LastChangedBy: alistair $
% $LastChangedDate: 2012-06-04 15:40:13 -0400 (Mon, 04 Jun 2012) $
% $Revision: 28 $
% Originally written on GLNXA64 by Alistair Johnson, 09-May-2012 11:52:57
% Contact: alistairewj@gmail.com
if nargin<2
error('2 arguments required.');
end
if ~iscell(field) || ...
size(field,1) ~= size(data,1) || size(field,2) ~= size(data,2)
error('Field must be a cell array of equal size to data');
end
N = size(data,1);
for k=1:N
f_t = field{k,2}; % field time
d_t = data{k,2}; % data time
%=== Sort field time into data time
t = [f_t;d_t];
[t,idxSort] = sort(t,1,'ascend');
idxSortNew = idxSort <= numel(f_t);
idxSortF = find(idxSortNew==1);
idxSortD = find(idxSortNew==0);
%=== Preallocate space for new values etc
M = numel(t); % Number of recordings for the observation
v = zeros(M,1); % values
l = cell(M,1); % labels
%=== Combine values
v(idxSortF) = field{k,4};
v(idxSortD) = data{k,4};
%=== Combine labels
l(idxSortF) = field{k,3};
l(idxSortD) = data{k,3};
%=== Push to output
data{k,2} = t;
data{k,3} = l;
data{k,4} = v;
end
end