wolffd@0: function sig = som_drsignif(sigmea,Cm)
wolffd@0: 
wolffd@0: % SOM_DRSIGNIF Significance measure from confusion matrix between two clusters and a rule.
wolffd@0: %
wolffd@0: % sig = som_drsignif(sigmea,Cm)
wolffd@0: % 
wolffd@0: %  sigmea   (string) significance measure: 'accuracy', 
wolffd@0: %                    'mutuconf' (default), or 'accuracyI'.
wolffd@0: %                    (See definitions below).
wolffd@0: %  Cn                Vectorized confusion matrix, or a matrix of such vectors.
wolffd@0: %           (vector) [a, c, b, d] (see below)
wolffd@0: %           (matrix) [[a1,c1,b1,d1], ..., [an,cn,bn,dn]]
wolffd@0: %
wolffd@0: %  sig      (vector) length=n, significance values 
wolffd@0: %
wolffd@0: % The confusion matrix Cm below between group (G) and contrast group (not G)
wolffd@0: % and rule (true - false) is used to determine the significance values:
wolffd@0: %
wolffd@0: %          G    not G    
wolffd@0: %       ---------------    accuracy  = (a+d) / (a+b+c+d)
wolffd@0: % true  |  a  |   b   |    
wolffd@0: %       |--------------    mutuconf  =  a*a  / ((a+b)(a+c)) 
wolffd@0: % false |  c  |   d   | 
wolffd@0: %       ---------------    accuracyI =   a   / (a+b+c)
wolffd@0: %
wolffd@0: % See also  SOM_DREVAL, SOM_DRMAKE.
wolffd@0: 
wolffd@0: % Contributed to SOM Toolbox 2.0, March 4th, 2002 by Juha Vesanto
wolffd@0: % Copyright (c) by Juha Vesanto
wolffd@0: % http://www.cis.hut.fi/projects/somtoolbox/
wolffd@0: 
wolffd@0: % Version 2.0beta juuso 040302
wolffd@0: 
wolffd@0: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
wolffd@0: %% input arguments
wolffd@0: 
wolffd@0: true_x     = Cm(:,1); % x     = in group
wolffd@0: false_x    = Cm(:,2); % false = rule is false
wolffd@0: true_y     = Cm(:,3); % true  = rule is true
wolffd@0: false_y    = Cm(:,4); % y     = not in group
wolffd@0: 
wolffd@0: true_items = true_x + true_y; 
wolffd@0: x_items    = true_x + false_x; 
wolffd@0: all_items  = true_x + false_x + true_y + false_y; 
wolffd@0: true_or_x  = x_items + true_items - true_x; 
wolffd@0: 
wolffd@0: switch sigmea, 
wolffd@0: case 'mutuconf',
wolffd@0:     % mutual confidence, or relevance (as defined in WSOM2001 paper)
wolffd@0:     sig = zeros(size(true_x)); 
wolffd@0:     i = find(true_items>0 & x_items>0); 
wolffd@0:     sig(i) = (true_x(i).^2) ./ (true_items(i).*x_items(i)); 
wolffd@0: case 'accuracy', 
wolffd@0:     % accuracy 
wolffd@0:     sig = (true_x + false_y) ./ all_items;
wolffd@0: case 'accuracyI', 
wolffd@0:     % accuracy such that false_y is left out of consideration
wolffd@0:     sig = true_x./true_or_x;
wolffd@0: otherwise, 
wolffd@0:     error(['Unrecognized significance measures: ' sigmea]);
wolffd@0: end 
wolffd@0: 
wolffd@0: return;