eeg_lat2point

 eeg_lat2point() - convert latencies in time units relative to the
                   time locking event of an eeglab() data epoch to 
                   latencies in data points (assuming concatenated epochs).
 Usage:
       >> [newlat] = eeg_lat2point( lat_array, epoch_array,...
                                 srate, timelimits, timeunit);
 Inputs:
   lat_array   - latency array in 'timeunit' units (see below)
   epoch_array - epoch number for each latency
   srate       - data sampling rate in Hz
   timelimits  - [min max] epoch timelimits in 'timeunit' units (see below)
   timeunit    - time unit relative to seconds. Default is 1 = seconds.

 Outputs:
   newlat      - converted latency values in points assuming concatenated
                 data epochs (see eeglab() event structure)

 Author: Arnaud Delorme, CNL / Salk Institute, 2 Mai 2002

 See also: eeg_point2lat(), eeglab()

0001 % eeg_lat2point() - convert latencies in time units relative to the
0002 %                   time locking event of an eeglab() data epoch to
0003 %                   latencies in data points (assuming concatenated epochs).
0004 % Usage:
0005 %       >> [newlat] = eeg_lat2point( lat_array, epoch_array,...
0006 %                                 srate, timelimits, timeunit);
0007 % Inputs:
0008 %   lat_array   - latency array in 'timeunit' units (see below)
0009 %   epoch_array - epoch number for each latency
0010 %   srate       - data sampling rate in Hz
0011 %   timelimits  - [min max] epoch timelimits in 'timeunit' units (see below)
0012 %   timeunit    - time unit relative to seconds. Default is 1 = seconds.
0013 %
0014 % Outputs:
0015 %   newlat      - converted latency values in points assuming concatenated
0016 %                 data epochs (see eeglab() event structure)
0017 %
0018 % Author: Arnaud Delorme, CNL / Salk Institute, 2 Mai 2002
0019 %
0020 % See also: eeg_point2lat(), eeglab()
0021 
0022 % Copyright (C) 2 Mai 2002 Arnaud Delorme, Salk Institute, arno@salk.edu
0023 %
0024 % This program is free software; you can redistribute it and/or modify
0025 % it under the terms of the GNU General Public License as published by
0026 % the Free Software Foundation; either version 2 of the License, or
0027 % (at your option) any later version.
0028 %
0029 % This program is distributed in the hope that it will be useful,
0030 % but WITHOUT ANY WARRANTY; without even the implied warranty of
0031 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0032 % GNU General Public License for more details.
0033 %
0034 % You should have received a copy of the GNU General Public License
0035 % along with this program; if not, write to the Free Software
0036 % Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
0037 
0038 function newlat = eeg_lat2point( lat_array, epoch_array, srate, timewin, timeunit);
0039 
0040 if nargin <4
0041     help eeg_lat2point;
0042     return;
0043 end;    
0044 if nargin <5
0045     timeunit = 1;
0046 end;
0047 
0048 if length(lat_array) ~= length(epoch_array)
0049     if length(epoch_array)~= 1
0050         disp('eeg_lat2point: latency and epochs must have the same length'); return;
0051     else
0052         epoch_array = ones(1,length(lat_array))*epoch_array;
0053     end;
0054 end;
0055 if length(timewin) ~= 2
0056     disp('eeg_lat2point: timelimits must have length 2'); return;
0057 end;
0058 if iscell(epoch_array)
0059     epoch_array = [ epoch_array{:} ];
0060 end;
0061 if iscell(lat_array)
0062     lat_array = [ lat_array{:} ];
0063 end
0064 
0065 timewin = timewin*timeunit;
0066 pnts = (timewin(2)-timewin(1))*srate+1;
0067 newlat  = (lat_array*timeunit-timewin(1))*srate+1 + (epoch_array-1)*pnts;