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# closest

## (Toolbox/closest.m in BrainStorm 2.0 (Alpha))

### Function Synopsis

    [pt_array2,pt2i,pt_array1,pt1i,dist] = closest(array1,array2);

### Help Text

    CLOSEST - Find point in one array closest to point in another array
     function [pt_array2,pt2i,pt_array1,pt1i,dist] = closest(array1,array2);
     find point the row in array2 closest in a Euclidean sense to locations in
     array1.  return as pt_array2.
     Optionally, pt_array1 is point in array1 closest to array2.
     Each row one multidimensional location.
     Optionally, return index pt2i and pt1i giving corresponding row number
     of closest elements.
     dist is the Euclidean distance between the two points

     (Note reversal of output arguments compared with input.  This reversal
     makes this function compatible with earlier versions of "closest".
     Can be called as closest([x y z],array), returning member in array.)

     See also CLUSTER, NEIGHBOR

### Cross-Reference Information

This function is called by

    source_grids                       C:\BrainStorm_2001\Toolbox\source_grids.m

### Listing of function C:\BrainStorm_2001\Toolbox\closest.m

    function [pt_array2,pt2i,pt_array1,pt1i,dist] = closest(array1,array2);
    %CLOSEST - Find point in one array closest to point in another array
    % function [pt_array2,pt2i,pt_array1,pt1i,dist] = closest(array1,array2);
    % find point the row in array2 closest in a Euclidean sense to locations in
    % array1.  return as pt_array2.
    % Optionally, pt_array1 is point in array1 closest to array2.
    % Each row one multidimensional location.
    % Optionally, return index pt2i and pt1i giving corresponding row number
    % of closest elements.
    % dist is the Euclidean distance between the two points
    %
    % (Note reversal of output arguments compared with input.  This reversal
    % makes this function compatible with earlier versions of "closest".
    % Can be called as closest([x y z],array), returning member in array.)
    %
    % See also CLUSTER, NEIGHBOR

    %<autobegin> ---------------------- 26-May-2004 11:29:53 -----------------------
    % --------- Automatically Generated Comments Block Using AUTO_COMMENTS ---------
    %
    % CATEGORY: Utility - Numeric
    %
    % At Check-in: $Author: Mosher $  $Revision: 14 $  $Date: 5/26/04 9:59a $
    %
    % This software is part of BrainStorm Toolbox Version 2.0 (Alpha) 24-May-2004
    %
    % Principal Investigators and Developers:
    % ** Richard M. Leahy, PhD, Signal & Image Processing Institute,
    %    University of Southern California, Los Angeles, CA
    % ** John C. Mosher, PhD, Biophysics Group,
    %    Los Alamos National Laboratory, Los Alamos, NM
    % ** Sylvain Baillet, PhD, Cognitive Neuroscience & Brain Imaging Laboratory,
    %    CNRS, Hopital de la Salpetriere, Paris, France
    %
    % See BrainStorm website at http://neuroimage.usc.edu for further information.
    %
    % Copyright (c) 2004 BrainStorm by the University of Southern California
    % This software distributed  under the terms of the GNU General Public License
    % as published by the Free Software Foundation. Further details on the GPL
    % license can be found at http://www.gnu.org/copyleft/gpl.html .
    %
    % FOR RESEARCH PURPOSES ONLY. THE SOFTWARE IS PROVIDED "AS IS," AND THE
    % UNIVERSITY OF SOUTHERN CALIFORNIA AND ITS COLLABORATORS DO NOT MAKE ANY
    % WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF
    % MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, NOR DO THEY ASSUME ANY
    % LIABILITY OR RESPONSIBILITY FOR THE USE OF THIS SOFTWARE.
    %<autoend> ------------------------ 26-May-2004 11:29:53 -----------------------

    % ----------------------------- Script History ---------------------------------
    % JCM        1991  Creation
    % JCM 20-Jul-1993  Handle multiple points
    % modified JCM 10/29/99 to use repmat function instead of kron for speed
    %  use sum(x,2) instead of sum(x',2);
    %  probably should consider shift to column vectors, but legacy code here.
    % JCM 19-May-2004  Comments cleaning
    % ----------------------------- Script History ---------------------------------

    [m2,n2] = size(array2);
    [m1,n1] = size(array1);
    if(n2 ~= n1),
      error(sprintf(...
      'CLOSEST: Arrays are not of same column size: %.0f, %.0f',n1,n2));
    end

    if(0) % old code
       array2 = kron(ones(m1,1),array2);
       array1 = kron(array1,ones(m2,1));
    else % new code 10/29/99
       if(m1 > 1), % multiple rows in the first array
          array2 = repmat(array2,m1,1);
          array1 = repmat(array1,[1 1 m2]);
          array1 = shiftdim(array1,2);
          array1 = reshape(array1(:),[m1*m2 n1]); % same as above kron without the multiply
       else % only a single row in array1
          array1 = array1(ones(m2,1),:); % simple rep out to match array2
       end
    end

    darray = array2 - array1;  % all combinations
    if(n1 > 1),
      darray = sum(darray.^2,2); % squared Euclidean distance, no need for sqrt
      [dist,i] = min(darray);  % closest point
      dist = sqrt(dist);  % Euclidean distance
    else
      darray = abs(darray); % one dimensional vector
      [dist,i] = min(darray);  % closest point
    end

    pt_array2 = array2(i,:);

    if(nargout > 1),
       pt2i = rem((i-1),m2)+1;  % index in orginal arrays
    else
       return % only wanted the row vector, not the index
    end

    if(nargout > 2), % also want the location in the first array
       pt_array1 = array1(i,:);
       pt1i = floor((i-1)/m2)+1;
    end

    return

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