modtrset.m

FISMAT accommodates different arithmetic operators, fuzzification and defuzzification algorithm, imp

function [lib,c,areas] = modtrset(range,no_of_sets)

% [lib,c,areas] = modtrset(range,no_of_sets)
%
% Modeling of trapezoidal fuzzy sets with the mouse.
% (Left mouse button picks points)
% Each trapecoid is characterised by for points which are picked up with
% the mouse FROM LEFT TO RIGHT describing a trapecoid (or triangle).
% If the first/fourth point is not near y=0, a to the left/right open 
% trapecoid is assumed. The points two and third must lie near y=1. (not
% exactly-this is done automatically).
% If the function is invoked without any parameters, you are ask for the 
% x-range and number of sets in the library.
%
% For use with parameters: (no use of the mouse)
% Range is a POSITIVE NUMBER !. xfrom=-xto. 
% no_of_sets = number of sets in the library.
%
% lib is the library of fuzzy sets in the compact form. 4 characteristic 
% points describing a general trapecoid - one per collumn.
% c is a vector with the local FAM-rule centroids.
% areas is a vector with the area of the local FAM-rules.
%
% FSTB - Fuzzy Systems Toolbox for MATLAB
% Copyright (c) 1993-1996 by Olaf Wolkenhauer
% Control Systems Centre at UMIST
% Manchester M60 1QD, UK
%
% 20-April-1994

if nargin==0,
  disp('Modeling trapecoidal sets with the mouse :')
  disp('Left mouse button picks points.')
  disp('Each trapecoid is characterised by four points from left to right.')
  xrange(2)=abs(input('Universe of discourse. Domain space X +- : '));
  xrange(1)=-1*xrange(2);
  no_of_sets=input('Number of library subsets in the x-range : ');
else
  xrange(2)=range;
  xrange(1)=-1*xrange(2);
end;
clf; axis([xrange(1) xrange(2) 0 1.2]);
hold on; grid on
% the hole library is stored in a 4 x no_of_sets matrix:
lib=zeros(4,no_of_sets); 
%  Each trapezoid in a column with the characteristic points.
y=zeros(4,no_of_sets); y(2,:)=ones(1,no_of_sets); 
y(3,:)=ones(1,no_of_sets);
but=1;                              % button 1=left button.
for set=1:no_of_sets,
  for co=1:4
    title(['set no: ',num2str(set),' point no: ',num2str(co)]);
    [xi,yi,but]=ginput(1);
    yi=round(yi);        
    plot(xi,yi,'go')
    lib(co,set)=xi;
    y(co,set)=yi;
  end; 
  plot(lib(:,set),y(:,set));         % Determing open trapecoids:
  if y(1,set)==1, lib(1,set)= -inf, end;
  if y(4,set)==1, lib(4,set)= inf, end;
end;
hold off; 
clf; 
hold on;
plot_set(lib);
for co=1:no_of_sets,                 % determine the local centroids.
  c(co)=(lib(2,co)+lib(3,co))/2;
end;
for co=1:no_of_sets,                 % local area of general trapezoids.
areas(co)=0.5*(lib(2,co)-lib(1,co))+(lib(3,co)-lib(2,co))+0.5*(lib(4,co)-lib(3,co));
end;   
xlabel('universe of discourse');
ylabel('membership');
grid on; hold off;