csort.m

控制系统计算机辅助设计——MATLAB语言与应用(源代码）

function [cs,so]=csort(c,f)
%CSORT  Sort columns into continuous vectors.
%       CSORT(C) sorts the columns of C into
%       continuous vectors by rearranging the columns
%       one row at a time to minimize the differences
%       between the rows.
%
%       [CS,SO]=CSORT(C) also returns the sorting matrices
%       in MVFR form such that
%       CS=FMULF(W,C,SO)  where length(W) = number of rows of C.
%
%       [CS,SF]=CSORT(C,F) rearranges the columns of the component
%       matrices of the MVFR matrix F in the same way as the
%       columns of C are rearranged.
%       This can be used to preserve the eigenvalue/eigenvector
%       relationship while making the eigenvalues into
%       continuous curves.
%       See FEIG

%       Dr M.P. Ford 4th August 1987
% Copyright (c) 1987 by GEC Engineering Research Centre & Cambridge Control Ltd
%       MRN0019

ni=nargin;
no=nargout;
[m,n]=size(c);
if n==1
   error('Cannot sort one column');
end
if m==1
   error('Cannot sort one row');
end
if (ni==2)&(no~=2)
      error('Inconsistent number of Input and Output arguments');
elseif ni==2  % must have 2 outputs
  [mf,nf]=fsize(c(:,1),f);
  if n~=nf
   error('Columns of component matrices of F not equal to the columns of C');
  end
  so=f;
else   % ie  ni==1
  if no==2
     so=eyef(c(:,1),n);
     f=so;
  end % if no==2
end  % if (ni==2)&(no~=2)
id=eye(n);
d=id;
infinity=ones(1,n)*2/eps;   % Note +and- inf is always returned
			    % as the minimun from the MIN function
cs=c;
k=1:n;

for j=1:m-1
  x=zeros(n);
  for i=1:n
     d(i,:)=abs(cs(j,:)-cs(j+1,i));
  end  % for i=1:n
  for i=1:n
     [dmin,di]=min(d);
     [dmin,dj]=min(dmin);
     x(di(dj),dj)=1;
     d(di(dj),:)=infinity;
     d(:,dj)=infinity';
  end     % for i=i:n
  if any(any(x~=id))  % swap the columns below this point.
    c(j+1:m,:)=cs(j+1:m,:);
    for i=1:n
       cs(j+1:m,i)=c(j+1:m,x(:,i));
    end
    if no==2         % only do this if required
      f(1+j*n:m*n,:)=so(1+j*n:m*n,:);
      for i=j:(m-1)
	so(k+n*i,:)=f(k+n*i,:)*x;
      end
    end  % if no==2
  end   % if any(any(x~=id))
end  % for j=1:m-1