source: distools/pe_affine.m @ 33

%PE_AFFINE Define and execute Pseudo Eclidean Affine mappings
%
%   W = PE_AFFINE(W,SIG)
%   F = PE_AFFINE(A,W)
%   F = A*W

function argout = pe_affine(arg1,arg2)

if ismapping(arg1)  % definition of PE mapping
        isaffine(arg1);
        if length(arg2) ~= 2
                error('Signature should have two components')
        end
        [n1,n2] = size(arg1);
        if sum(arg2) ~= n1
                error('Sum of signature numbers should equal input dimension of mapping')
        end
        par.map = arg1;
        par.sig = arg2;
        argout = mapping(mfilename,'trained',par,getlabels(arg1),n1,n2);
else
        isdataset(arg1);
        ismapping(arg2);
        w = getdata(arg2,'map');
        sig = getdata(arg2,'sig');
        if sig(2) ~= 0;
                data = getdata(w);
                data.rot = -data.rot;
                data.offset = zeros(1,size(arg2,2));
                v = setdata(w,data);
                [m,k] = size(arg1);
                if sig(1) ~= 0
                        argout = [arg1(:,1:sig(1)) zeros(m,sig(2))]*w;
                else
                        argout = setdata(arg1,zeros(m,k))*w;
                end
                argout = argout + [setdata(arg1,zeros(m,sig(1))) arg1(:,sig(1)+1:end)]*v;
        else % no negative directions: back in Euclidean case
                argout = arg1*w;
        end
end