--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@matrix/inv.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,109 @@
+% INV evaluates the inverse for matrix object.
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% DESCRIPTION: INV evaluates the inverse for matrix objects.
+%
+% CALL:        obj = inv(mat)
+%              obj = mat.inv()
+%
+% <a href="matlab:utils.helper.displayMethodInfo('matrix', 'inv')">Parameters Description</a>
+%
+% VERSION:     $Id: inv.m,v 1.10 2011/04/08 08:56:31 hewitson Exp $
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function varargout = inv(varargin)
+  
+  % Check if this is a call for parameters
+  if utils.helper.isinfocall(varargin{:})
+    varargout{1} = getInfo(varargin{3});
+    return
+  end
+  
+  % Check if the method was called by another method
+  callerIsMethod = utils.helper.callerIsMethod;
+  
+  % Collect input variable names
+  in_names = cell(size(varargin));
+  for ii = 1:nargin,in_names{ii} = inputname(ii);end
+  
+  % Collect all matrices and plists
+  [as, matrix_invars, rest] = utils.helper.collect_objects(varargin(:), 'matrix', in_names);
+  [pl, pl_invars, rest]     = utils.helper.collect_objects(varargin(:), 'plist', in_names);
+  
+  % Decide on a deep copy or a modify
+  bs = copy(as, nargout);
+  
+  % Combine input plists and default plist
+  usepl = parse(pl, getDefaultPlist());
+  
+  % do dimension check
+  [rw,cl] = size(bs.objs);
+  if rw ~= cl
+    error('### Matrix must be square');
+  end
+  
+  % get the determinant
+  DA = det(bs);
+  
+  % build cofactor matrix
+  C = copy(bs,1);
+  for ii = 1:rw % raw index
+    for jj = 1:cl % column index
+      % ij Minor of A
+      MA = copy(bs,1);
+      MA.objs(ii,:) = [];
+      MA.objs(:,jj) = [];
+      % cofactor
+      C.objs(ii,jj) = det(MA).*((-1)^(ii+jj));
+    end
+  end
+  % get the transpose of cofactors matrix
+  CT = transpose(C);
+  % do inverse
+  bs = CT./matrix(DA);
+  
+  if ~callerIsMethod
+    % set name
+    bs.setName(sprintf('inv(%s)', in_names{1}));
+    
+    % Add history
+    bs.addHistory(getInfo('None'), usepl, [matrix_invars(:)], [as(:).hist]);
+  end
+  
+  varargout{1} = bs;
+  
+end
+
+%--------------------------------------------------------------------------
+% Get Info Object
+%--------------------------------------------------------------------------
+function ii = getInfo(varargin)
+  
+  if nargin == 1 && strcmpi(varargin{1}, 'None')
+    sets = {};
+    pl  = [];
+  else
+    sets = {'Default'};
+    pl  = getDefaultPlist;
+  end
+  % Build info object
+  ii = minfo(mfilename, 'matrix', 'ltpda', utils.const.categories.op, '$Id: inv.m,v 1.10 2011/04/08 08:56:31 hewitson Exp $', sets, pl);
+end
+
+%--------------------------------------------------------------------------
+% Get Default Plist
+%--------------------------------------------------------------------------
+
+function plout = getDefaultPlist()
+  persistent pl;
+  if ~exist('pl', 'var') || isempty(pl)
+    pl = buildplist();
+  end
+  plout = pl;
+end
+
+function pl = buildplist()
+  pl = plist.EMPTY_PLIST;
+end
+