wolffd@0: function unit_coord=som_vis_coords(lattice, msize)
wolffd@0: 
wolffd@0: %SOM_VIS_COORDS Unit coordinates used in visualizations.
wolffd@0: % 
wolffd@0: % Co = som_vis_coords(lattice, msize)
wolffd@0: %
wolffd@0: %  Co = som_vis_coords('hexa',[10 7])
wolffd@0: %  Co = som_vis_coords('rectU',[10 7])
wolffd@0: %
wolffd@0: %  Input and output arguments: 
wolffd@0: %   lattice   (string) 'hexa', 'rect', 'hexaU' or 'rectU'
wolffd@0: %   msize     (vector) grid size in a 1x2 vector    
wolffd@0: %
wolffd@0: %   Co        (matrix) Mx2 matrix of unit coordinates, where 
wolffd@0: %               M=prod(msize) for 'hexa' and 'rect', and 
wolffd@0: %               M=(2*msize(1)-1)*(2*msize(2)-1) for 'hexaU' and 'rectU'
wolffd@0: %
wolffd@0: % This function calculates the coordinates of map units on a 'sheet'
wolffd@0: % shaped map with either 'hexa' or 'rect' lattice as used in the
wolffd@0: % visualizations. Note that this slightly different from the
wolffd@0: % coordinates provided by SOM_UNIT_COORDS function. 
wolffd@0: %
wolffd@0: % 'rectU' and 'hexaU' gives the coordinates of both units and the
wolffd@0: % connections for u-matrix visualizations.
wolffd@0: %
wolffd@0: % For more help, try 'type som_vis_coords' or check out online documentation.
wolffd@0: % See also SOM_UNIT_COORDS, SOM_UMAT, SOM_CPLANE, SOM_GRID.
wolffd@0: 
wolffd@0: %%%%%%%%% DETAILED DESCRIPTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0: %
wolffd@0: % PURPOSE 
wolffd@0: % 
wolffd@0: % Returns coordinates of the map units for map visualization
wolffd@0: %
wolffd@0: % SYNTAX
wolffd@0: %
wolffd@0: %  Co = som_vis_coords(lattice, msize)
wolffd@0: %
wolffd@0: % DESCRIPTION
wolffd@0: %
wolffd@0: % This function calculates the coordinates of map units in 'hexa' and
wolffd@0: % 'rect' lattices in 'sheet' shaped map for visualization purposes. It
wolffd@0: % differs from SOM_UNIT_COORDS in the sense that hexagonal lattice is
wolffd@0: % calculated in a "wrong" way in order to get integer coordinates for
wolffd@0: % the units. Another difference is that it may be used to calculate
wolffd@0: % the coordinates of units _and_ the center points of the lines
wolffd@0: % connecting them (edges) by using 'hexaU' or 'rectU' for lattice. 
wolffd@0: % This property may be used for drawing u-matrices.
wolffd@0: %
wolffd@0: % The unit number 1 is set to (ij) coordinates (1,1)+shift
wolffd@0: %                 2                            (2,1)+shift
wolffd@0: %
wolffd@0: %  ... columnwise
wolffd@0: % 
wolffd@0: %             n-1th                        (n1-1,n2)+shift
wolffd@0: %             nth                            (n1,n2)+shift
wolffd@0: %
wolffd@0: % where grid size = [n1 n2] and shift is zero, except for 
wolffd@0: % the even lines of 'hexa' lattice, for which it is +0.5.
wolffd@0: %
wolffd@0: % For 'rectU' and 'hexaU' the unit coordinates are the same and the
wolffd@0: % coordinates for connections are set according to these. In this case
wolffd@0: % the ordering of the coordinates is the following:
wolffd@0: %   let
wolffd@0: %     U  = som_umat(sMap); U=U(:); % make U a column vector
wolffd@0: %     Uc = som_vis_coords(sMap.topol.lattice, sMap.topol.msize); 
wolffd@0: %   now the kth row of matrix Uc, i.e. Uc(k,:), contains the coordinates 
wolffd@0: %   for value U(k). 
wolffd@0: %
wolffd@0: % REQUIRED INPUT ARGUMENTS 
wolffd@0: %
wolffd@0: %  lattice  (string) The local topology of the units: 
wolffd@0: %                    'hexa', 'rect', 'hexaU' or 'rectU'
wolffd@0: %  msize    (vector) size 1x2, defining the map grid size. 
wolffd@0: %                    Notice that only 2-dimensional grids
wolffd@0: %                    are allowed.
wolffd@0: %
wolffd@0: % OUTPUT ARGUMENTS
wolffd@0: % 
wolffd@0: %  Co       (matrix) size Mx2, giving the coordinates for each unit.
wolffd@0: %                    M=prod(msize) for 'hexa' and 'rect', and 
wolffd@0: %                    M=(2*msize(1)-1)*(2*msize(2)-1) for 'hexaU' and 'rectU'
wolffd@0: %
wolffd@0: % FEATURES
wolffd@0: % 
wolffd@0: % Only 'sheet' shaped maps are considered. If coordinates for 'toroid'
wolffd@0: % or 'cyl' topologies are required, you must use SOM_UNIT_COORDS
wolffd@0: % instead.
wolffd@0: %
wolffd@0: % EXAMPLES
wolffd@0: %
wolffd@0: % Though this is mainly a subroutine for visualizations it may be
wolffd@0: % used, e.g., in the following manner:
wolffd@0: %
wolffd@0: % % This makes a hexagonal lattice, where the units are rectangular
wolffd@0: % % instead of hexagons.
wolffd@0: %    som_cplane('rect',som_vis_coords('hexa',[10 7]),'none');
wolffd@0: %
wolffd@0: % % Let's make a map and calculate a u-matrix: 
wolffd@0: %    sM=som_make(data,'msize',[10 7],'lattice','hexa');
wolffd@0: %    u=som_umat(sM); u=u(:);
wolffd@0: % % Now, these produce equivalent results:
wolffd@0: %    som_cplane('hexaU',[10 7],u);
wolffd@0: %    som_cplane(vis_patch('hexa')/2,som_vis_coords('hexaU',[10 7]),u);
wolffd@0: %
wolffd@0: % SEE ALSO
wolffd@0: %
wolffd@0: % som_grid         Visualization of a SOM grid
wolffd@0: % som_cplane       Visualize a 2D component plane, u-matrix or color plane
wolffd@0: % som_barplane     Visualize the map prototype vectors as bar diagrams
wolffd@0: % som_plotplane    Visualize the map prototype vectors as line graphs
wolffd@0: % som_pieplane     Visualize the map prototype vectors as pie charts
wolffd@0: % som_unit_coords  Locations of units on the SOM grid
wolffd@0: 
wolffd@0: % Copyright (c) 1999-2000 by the SOM toolbox programming team.
wolffd@0: % http://www.cis.hut.fi/projects/somtoolbox/             
wolffd@0: 
wolffd@0: % Version 2.0beta Johan 201099 juuso 261199
wolffd@0: 
wolffd@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0: 
wolffd@0: if ~vis_valuetype(msize,{'1x2'}),
wolffd@0:   error('msize must be a 1x2 vector.')
wolffd@0: end
wolffd@0: 
wolffd@0: if vis_valuetype(lattice,{'string'})
wolffd@0:   switch lattice
wolffd@0:   case {'hexa', 'rect'}
wolffd@0:     munits=prod(msize);
wolffd@0:     unit_coord(:,1)=reshape(repmat([1:msize(2)],msize(1),1),1,munits)';
wolffd@0:     unit_coord(:,2)=repmat([1:msize(1)]',msize(2),1);
wolffd@0:     if strcmp(lattice,'hexa')
wolffd@0:       % Move even rows by .5
wolffd@0:       d=rem(unit_coord(:,2),2) == 0;   
wolffd@0:       unit_coord(d,1)=unit_coord(d,1)+.5;
wolffd@0:     end
wolffd@0:   case {'hexaU','rectU'}
wolffd@0:     msize=2*msize-1; munits=prod(msize);
wolffd@0:     unit_coord(:,1)=reshape(repmat([1:msize(2)],msize(1),1),1,munits)';
wolffd@0:     unit_coord(:,2)=repmat([1:msize(1)]',msize(2),1);
wolffd@0:     if strcmp(lattice,'hexaU')
wolffd@0:       d=rem(unit_coord(:,2),2) == 0;   
wolffd@0:       unit_coord(d,1)=unit_coord(d,1)+.5;
wolffd@0:       d=rem(unit_coord(:,2)+1,4) == 0; 
wolffd@0:       unit_coord(d,1)=unit_coord(d,1)+1;
wolffd@0:     end
wolffd@0:     unit_coord=unit_coord/2+.5;
wolffd@0:   otherwise
wolffd@0:     error([ 'Unknown lattice ''' lattice '''.']);
wolffd@0:   end
wolffd@0: else
wolffd@0:   error('Lattice must be a string.');
wolffd@0: end