Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / nan-2.5.5 / row_col_deletion.m

diff --git a/octave_packages/nan-2.5.5/row_col_deletion.m b/octave_packages/nan-2.5.5/row_col_deletion.m
new file mode 100644 (file)
index 0000000..578687b
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+++ b/octave_packages/nan-2.5.5/row_col_deletion.m
@@ -0,0 +1,113 @@
+function [rix,cix] = row_col_deletion(d,c,w)
+% ROW_COL_DELETION selects the rows and columns for removing any missing values. 
+%    A heuristic based on maximizing the number of remaining sample values
+%    is used. In other words, if there are more rows than columns, it is 
+%    more likely that a row-wise deletion will be applied and vice versa. 
+% 
+%    [rix,cix] = row_col_deletion(d)
+%    [rix,cix] = row_col_deletion(d,c,w)
+% 
+% Input: 
+%    d        data (each row is a sample, each column a feature)
+%    c        classlabels (not really used) [OPTIONAL]
+%    w        weight for each sample vector [OPTIONAL]   
+% Output:
+%    rix      selected samples
+%    cix      selected columns    
+% 
+%   d(rix,cix) does not contain any NaN's i.e. missing values      
+% 
+% see also: TRAIN_SC, TEST_SC
+ 
+%      $Id$
+%      Copyright (C) 2009,2010 by Alois Schloegl <alois.schloegl@gmail.com>
+%       This function is part of the NaN-toolbox
+%       http://pub.ist.ac.at/~schloegl/matlab/NaN/
+
+% This program is free software; you can redistribute it and/or
+% modify it under the terms of the GNU General Public License
+% as published by the Free Software Foundation; either version 3
+% of the  License, or (at your option) any later version.
+% 
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+% 
+% You should have received a copy of the GNU General Public License
+% along with this program; if not, write to the Free Software
+% Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
+
+
+if nargin > 2,
+       if isempty(w) || all(w==w(1)), 
+               ix = ~isnan(c);
+       else
+               ix = ~any(isnan(c) | isnan(w));
+       end; 
+       d = d(ix,:);    %% ignore samples with invalid c or w
+       w = w(ix,:);
+
+elseif nargin > 1,
+       d = d(~isnan(c),:);     %% ignore samples with invalid c or w
+        w = [];
+else
+        w = [];        
+end;   
+
+
+if 0, 
+       % decides whether row-wise or column-wise deletion removes less data. 
+       % rix and cix are the resulting index vectors
+       % either row-wise or column-wise deletion, but not a combination of both, is used. 
+       % this is obsolete
+       
+               n   = numel(d); 
+               cix = find(~any(isnan(d),1)); 
+               rix = find(~any(isnan(d),2)); 
+               nr  = length(rix)*size(d,2); % number of elements after row-wise deletion
+               nc  = length(cix)*size(d,1); % number of elements after column-wise deletion
+               
+               if (nr>nc)
+                       cix = 1:size(d,2);  % select all columns
+                       %fprintf(1,'row-wise deletion (%i,%i,%i)\n',n,nr,nc);           
+               else
+                       rix = 1:size(d,1);  % select all rows 
+                       %fprintf(1,'column-wise deletion (%i,%i,%i)\n',n,nr,nc);                
+               end; 
+
+else
+
+               %% a mix of row- and column-wise deletion is possible 
+               if ~isempty(w) && (abs(sum(w)-1) > log2(N)*eps || any(w<0) || any(~isfinite(w)))
+                       error('weight vector must contain only non-negative and finite values');
+               end; 
+               [N,M] = size(d); 
+               rix = ones(N,1); cix = ones(1,M);
+               while 1;
+                        e = ~isnan(d(rix>0,cix>0));
+                        if  ~isempty(w),
+                                colCost  = mean(e, 1, w(rix>0)/sum(w(rix>0)))';        % cost of deleting columns
+                        else
+                                colCost  = mean(e, 1)';        % cost of deleting columns
+                        end;         
+                        rowCost  = mean(e, 2);           % cost of deleting rows     
+                        [tmp,ix] = sort([colCost; rowCost]);
+                        
+                if abs(tmp(1)-1) < log2(N)*eps, break; end;        % stopping criterion
+
+                        if diff(tmp(1:2))==0, warning('row/col deletion: arbitrary selection [%i,%i]',ix(1:2)); end;  
+                        ix = ix(1);
+                        if (ix<=sum(cix))
+                                tmp = find(cix>0);
+                                cix(tmp(ix)) = 0;
+                        else
+                                tmp = find(rix>0);
+                                rix(tmp(ix-sum(cix))) = 0;
+                        end;
+                end; 
+                rix = find(rix);
+                cix = find(cix);
+
+end
+