comp.m

控制系统计算机辅助设计——MATLAB语言与应用(源代码）

function xout=comp(x,n)
%COMP   Compress a vector or matrix
%       COMP(X,n) returns the first element of X and every Nth+1
%       element thereafter, if X is vector
%               OR
%       the first row of X and every Nth+1 row
%       thereafter, if X is a matrix.
%       To compress a matrix column-wise use
%       COMP(X',n)'
%
%       The input argument n is optional.
%       If n is missing the default of 10 is used.
%       See also FCOMP,EXPD

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

nargs=nargin;
error(nargchk(1,2,nargs));
if nargs <2
    n = 10;
end
if n==1
  xout=x;
else
  [mx,nx]=size(x);
  if min(mx,nx)==1   % x is a vector
    p = (1:length(x));
    p = rem(p,n);
    p = p==1;
    xout = x(p);
  else              % x is a matrix
    p=(1:mx);
    p = rem(p,n);
    p = p==1;
    xout = x(p,:);
  end
end  % if n==1