fac2let.m

多维数据处理：MATLAB源程序用于处理多维数据

function [A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,X,Y,Z]=fac2let(Factors,DimX,Fac,LongForm);

% $ Version 1.02 $ Date 28. July 1998 $ Not compiled $
%
% ----------------------------------------------------
%       Convert 'Factors' to component matrices
% ----------------------------------------------------
%
%	Copyright
%	Claus A. Andersson 1995-1997
%	Chemometrics Group, Food Technology
%	Department of Food and Dairy Science
%	Royal Veterinary and Agricultutal University
%	Rolighedsvej 30, T254
%	DK-1958 Frederiksberg
%	Denmark
%
%	Phone 	[phone]
%	Fax	[phone]
%	E-mail	[e-mail]
%
%	
% [A,B,C]=fac2let(Factors,DimX,Fac);
% [A,B,C,D]=fac2let(Factors,DimX,Fac);
% [A,B,C,D,E]=fac2let(Factors,DimX,Fac);
%             .....
% [A,B,C,...,Z]=fac2let(Factors,DimX,Fac);
%
% This algorithm applies to the N-way case (2<N<25).
%
% If a fourth input is given a matrix will be calculated where
% the f'th column is the kronecker product of the f'th column
% of each loading matrix. This evidently only applies to models
% where the same number of factors are used for each mode.

if nargin<4
  Rp=DimX;
  Wp=Fac;
  if length(Wp)==1
     Wp=ones(1,length(DimX))*Wp;
  end

  if length(Factors)<sum(DimX.*Wp)
    error(' Too many components extracted')
  elseif length(Factors)~=sum(DimX.*Wp)
    disp([' Inconsistency in input parameters (maybe wrong number of components are extracted)'])
  end

  Cp=length(Rp(1,:));
  Txt='ABCDEFGHIJKLMNOPQRSTUVXYZ';
  FIdx0=cumsum([1 Rp(1:Cp-1).*Wp(1:Cp-1)]);
  FIdx1=cumsum([Rp.*Wp]);
  for c=1:Cp,
    str=[Txt(c) '='];
    str=[str 'reshape(Factors('];
    str=[str num2str(FIdx0(c))];
    str=[str ':'];
    str=[str num2str(FIdx1(c))];
    str=[str '),'];
    str=[str num2str(Rp(c))];
    str=[str ','];
    str=[str num2str(Wp(c))];
    str=[str ');'];
    %disp(str)
    eval(str)
  end;
else
  if any(Fac~=Fac(1))
    error(' The number of factors must be the same in every mode')
  end
  Fac=Fac(1);
  A=zeros(prod(DimX),Fac);
  for f=1:Fac
    L1=Factors(DimX(1)*(f-1)+1:DimX(1)*f);
    if length(DimX)>1
      L2=Factors(DimX(1)*Fac+DimX(2)*(f-1)+1:DimX(1)*Fac+DimX(2)*f);
      Z=kron(L2,L1);
      for i=3:length(DimX)
        L1=Factors(sum(DimX(1:i-1)*Fac)+DimX(i)*(f-1)+1:sum(DimX(1:i-1)*Fac)+DimX(i)*f);
        Z=kron(L1,Z);
      end
    else
     Z=L1;
    end
    A(:,f)=Z;
  end
end