brede_mat_minus

 brede_mat_minus      - Subtract a matrix from another

       function C = brede_mat_minus(A, B)

       Input:    A      'Mat' structure
                 B      'Mat' structure

       Property: Match  [ {off} | columns ] Matching of columns
                        before subtraction

       Output:   C      'Mat' structure

       This function will subtract one matrix from another (C = A-B)

       For 'match' set to 'columns': If the columns contains strings
       then the columns will be handled so the columns corresponding
       to the same strings are subtracted. This will make the number
       of columns at least as large as the largest matrix. The
       matching takes place in the brede_mat_match function.

       Any of the matrices might be a vector or a scalar.  

       Example:
         % Subtraction with equal sized matrices
         getfield(brede_mat_minus([1 2;3 4],[4 3;2 1]), 'matrix')

         % Subtraction with scalar
         M = brede_mat_minus(randn(100,100), 5)
         figure, hist(M.matrix(:), sqrt(length(M.matrix(:))));

         % Matching of columns 
         M1.columns = { 'First' 'Second' };
         M1.matrix  = [ 1 2 ];
         M2.columns = { 'Second' 'First' };
         M2.matrix  = [ 2 1 ];
         brede_mat_minus(M1,M2, 'match', 'columns')  % This gives a zero matrix

         % Substraction with a vector
         M1 = brede_mat_mat2mat(rand(100,100));
         M2 = brede_mat_mean(M1, 'type', 'rowmean');
         M3 = brede_mat_minus(M1, M2)
         M4 = brede_mat_mean(M3, 'type', 'rowmean');
         max(M4.matrix)

       See also BREDE, BREDE_MAT, BREDE_MAT_ADD, BREDE_MAT_DIVIDE,
                BREDE_MAT_MAT2MAT, BREDE_MAT_MATCH,
                BREDE_MAT_PRODUCT, BREDE_MAT_TRANSPOSE.

 $Id: brede_mat_minus.m,v 1.3 2006/02/01 19:07:58 fnielsen Exp $