con2dis.m

来自「FISMAT accommodates different arithmetic」· M 代码 · 共 52 行

function [Xdom,m,moments,areas] = con2dis(set,Nel)

% [Xdom,m,moments,areas] = con2dis(set,Nel)
%
% Converts compact triangular form (describing a continuous membership-
% function) in a discrete vector form.
% set is a 4xl matrix with l sets desribed with four characteristical
% points in a column.
% The universe of discourse is divided in n discrete points.
% Xdom is a 1xNel vector with the X domain. (The same for all sets)
% M is a lxNel matrix with the fit-value for one set in each row.
% The set in the first collumn (left) of the compact form, 
% corresponds to the first row in the matrix with the discrete sets.
% For discrete sets the moment of the membership-function is
% sum(X(i)*m(i)) i from 1 to Nel. (= Xdom*m')
% moments/areas=row vector with the first element corresponding to the most
% "negative" membership-function.
%
% FSTB - Fuzzy Systems Toolbox for MATLAB
% Copyright (c) 1993-1996 by Olaf Wolkenhauer
% Control Systems Centre at UMIST
% Manchester M60 1QD, UK
%
%       22-April-1994

[p,l]=size(set);
if p~=4, error('number of rows must be four - wrong set format!'),end;

m=zeros(l,Nel);
% finding infs from sets with left/right open trapezoids:
xmax=set(4,l); xmin=set(1,1);
if xmax==inf, set(4,l)=set(3,l);end;
if xmin==-inf,set(1,1)=set(2,1);end;
Xdom=linspace(set(1,1),set(4,l),Nel);
%sprintf('discretisation interval: %6.3f',x(n)-x(n-1));
% Using the function modlrset() for LR-fuzzy sets:
for co=1:l,
  al=set(2,co)-set(1,co); m1=set(2,co);
  be=set(4,co)-set(3,co); m2=set(3,co);
  m(co,:)=modlrset('tr','',[Xdom(1),Xdom(Nel),m1,m2,al,be,0,1],Nel);
end;
% Calculating the moments:
moments=zeros(1,l);
for co=1:l,
  moments(co)=Xdom*m(co,:)';
end;
% Calculating the areas:
areas=zeros(1,l);
for co=1:l,
  areas(co)=sum(m(co,:));
end;