view m-toolbox/classes/@matrix/det.m @ 50:7d2e2e065cf1
database-connection-manager
Update unit tests
author
Daniele Nicolodi <nicolodi@science.unitn.it>
date
Wed, 07 Dec 2011 17:24:37 +0100 (2011-12-07)
parents
f0afece42f48
children
line source
+ − % DET evaluates the determinant for matrix object.
+ − %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+ − %
+ − % DESCRIPTION: DET evaluates the determinant for matrix objects.
+ − % The objects must belong to the same class (e.g. ao, smodel, ...)
+ − % The result is an object of the class itself
+ − %
+ − % CALL: obj = det(mat)
+ − % obj = mat.det()
+ − %
+ − % <a href="matlab:utils.helper.displayMethodInfo('matrix', 'det')">Parameters Description</a>
+ − %
+ − % VERSION: $Id: det.m,v 1.13 2011/04/08 08:56:31 hewitson Exp $
+ − %
+ − %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+ −
+ − function out = det(varargin)
+ −
+ − callerIsMethod = utils.helper.callerIsMethod;
+ −
+ − if callerIsMethod
+ − as = [varargin{:}];
+ − else
+ − % Check if this is a call for parameters
+ − if utils.helper.isinfocall(varargin{:})
+ − out = getInfo(varargin{3});
+ − return
+ − end
+ −
+ − % 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);
+ −
+ − % Combine input plists and default plist
+ − usepl = parse(pl, getDefaultPlist());
+ − end
+ −
+ − % extract objects
+ − objmat = as.objs;
+ −
+ − % we check now the dimensionality to be sure to have a square matrix
+ − [rw, cl] = size(objmat);
+ − if rw ~= cl
+ − error('### Matrix must be square');
+ − end
+ −
+ − % Let's go with textbook definition
+ − switch cl
+ − case 0
+ − % To be compliant with definition.
+ − % Here we choose to output an ao, so we can have history;
+ − % if used with other objetcs (ao, smodel, ...) it will be promoted anyways
+ − out = ao(1);
+ − case 1
+ − out = objmat;
+ − case 2
+ − out = objmat(1,1) .* objmat(2,2) - objmat(2,1) .* objmat(1,2);
+ − otherwise
+ − dmod_minor = eval(sprintf('%s.initObjectWithSize(1,cl);', class(objmat)));
+ −
+ − % Cache these objects not to produce them iteratively
+ − coeff_minus = ao(-1);
+ − coeff_plus = ao(1);
+ − for jj = 1:cl
+ − Amod = objmat;
+ − Amod(1,:) = [];
+ − Amod(:,jj) = [];
+ − Am = matrix(Amod);
+ − if (-1).^(jj+1) > 0
+ − coeff = coeff_plus;
+ − else
+ − coeff = coeff_minus;
+ − end
+ − dmod_minor(jj) = objmat(1,jj) .* det(Am) * coeff;
+ − end
+ − % sum over elements
+ − out = dmod_minor(1);
+ − for kk = 2:numel(dmod_minor)
+ − out = out + dmod_minor(kk);
+ − end
+ − end
+ −
+ − if ~callerIsMethod
+ − % Set name
+ − out.setName(sprintf('det(%s)', in_names{1}));
+ −
+ − % Add history
+ − out.addHistory(getInfo('None'), usepl, {inputname(1)}, [as(:).hist]);
+ − end
+ −
+ − 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: det.m,v 1.13 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
+ −