init

FOTF Toolbox/@ppoly/collect.m

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+function p=collect(p) 
+% collect - collect like terms in ppoly objects
+%
+%    p=collect(p)
+%
+%   p - a ppoly object
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   a=p.a; na=p.na; 
+   [na,ii]=sort(na,'descend'); a=a(ii); ax=diff(na); key=1;
+   for i=1:length(ax)
+      if abs(ax(i))<=1e-10
+         a(key)=a(key)+a(key+1); a(key+1)=[]; na(key+1)=[];
+      else, key=key+1; end
+   end
+   ii=find(abs(a)~=0); a=a(ii); na=na(ii); p=ppoly(a,na);
+end

FOTF Toolbox/@ppoly/disp.m

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+function str=disp(p)
+% collect - collect like terms in ppoly objects
+%
+%    p=collect(p)
+%
+%   p - a ppoly object
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   np=p.na; p=p.a; 
+   if isempty(np), p=0; np=0; end
+   P=''; [np,ii]=sort(np,'descend'); p=p(ii); 
+   for i=1:length(p)
+      P=[P,'+',num2str(p(i)),'*s^{',num2str(np(i)),'}'];
+   end
+   P=P(2:end); P=strrep(P,'s^{0}',''); P=strrep(P,'+-','-'); 
+   P=strrep(P,'^{1}',''); P=strrep(P,'+1*s','+s'); 
+   P=strrep(P,'*+','+'); P=strrep(P,'*-','-');
+   P=strrep(P,'-1*s','-s'); nP=length(P); 
+   if nP>=3 && isequal(P(1:3),'1*s'), P=P(3:end); end
+   if P(end)=='*', P(end)=''; end 
+   if nargout==0, disp(P), else, str=P; end
+end

FOTF Toolbox/@ppoly/eq.m

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+function key=eq(p1,p2)
+% eq - test whether two PPOLY objects are equal or not
+%
+%    key=p1==p2
+%
+%   p1, p2 - the two PPOLY objects
+%   key = 1 for equal, otherwise key = 0
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   g=collect(p1-p2); key=isempty(g.a);
+end

FOTF Toolbox/@ppoly/freqw.m

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+function H=freqw(p,w)
+% freqw - get frequency response of ppoly object
+%
+%    H=freqw(p,w)
+%
+%   p - a ppoly object
+%   w - frequency vector
+%   H - frequency response data
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   for i=1:length(w), H(i)=p.a(:).'*(1i*w(i)).^p.na(:); end
+end

FOTF Toolbox/@ppoly/get.m

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+function p1=get(varargin)
+% get - get fields from ppoly object
+%
+%    a=get(p,'a') or na=get(p,'na') 
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   p=varargin{1};
+   if nargin==1 
+       s=sprintf('%f ,',p.a); disp(['  a: [' s(1:end-1) ']'])
+       s=sprintf('%f ,',p.na); disp([' na: [' s(1:end-1) ']'])
+   elseif nargin==2, key=varargin{2};
+       switch key 
+           case 'a', p1=p.a; case 'na', p1=p.na;
+           otherwise, error('Wrong field name used'), 
+       end
+   else, error('Wrong number of input argumants'); 
+   end
+end

FOTF Toolbox/@ppoly/isppoly.m

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+function key=isppoly(p)
+% isppoly - check whether input is an ppoly object
+%
+%    key=isppoly(p)
+%
+%   key returns 1 or 0
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   key=strcmp(class(p),'ppoly');
+end

FOTF Toolbox/@ppoly/latex.m

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+function strA=latex(p)
+% latex - convert ppoly object into LaTeX string
+%
+%    str=latex(p)
+%
+%   p - a ppoly object
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   str=disp(p); str=strrep(str,'*s','s'); 
+   if nargout==0, disp(str), else, strA=str; end
+end

FOTF Toolbox/@ppoly/minus.m

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+function p=minus(p1,p2)
+% minus - find the differences in two ppoly objects
+%
+%    p=p1-p2
+%
+%   p, p1, p2 - ppoly objects
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   p=p1+(-p2);
+end

FOTF Toolbox/@ppoly/mpower.m

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+function p1=mpower(p,n)
+% mpower - power of a ppoly object
+%
+%    p1=p^n
+%
+%   p - a ppoly object
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   if length(p.a)==1, p1=ppoly(p.a^n,p.na*n);
+   elseif n==floor(n)
+      if n<0, p.na=-p.na; n=-n; end
+      p1=ppoly(1); for i=1:n, p1=p1*p; end
+   else, error('n must be an integer'), end
+end

FOTF Toolbox/@ppoly/mrdivide.m

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+function p=mrdivide(p1,p2)
+% mrdivide - right divide ppoly objects
+%
+%    p=p1/p2
+%
+%   p, p1, p2 - ppoly objects
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   p1=collect(ppoly(p1)); p2=collect(ppoly(p2)); p=fotf(p2,p1);
+end

FOTF Toolbox/@ppoly/mtimes.m

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+function p=mtimes(p1,p2)
+% mtimes - product of two ppoly objects
+%
+%    p=p1*p2
+%
+%   p, p1, p2 - ppoly object
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   p1=ppoly(p1); p2=ppoly(p2); a=kron(p1.a,p2.a); 
+   na=kronsum(p1.na,p2.na); p=collect(ppoly(a,na));
+end

FOTF Toolbox/@ppoly/plus.m

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+function p=plus(p1,p2)
+% plus - sum of twp ppoly objects
+%
+%    p=p1+p2
+%
+%   p, p1, p2 - ppoly objects
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   p1=ppoly(p1); p2=ppoly(p2); 
+   a=[p1.a,p2.a]; na=[p1.na,p2.na]; p=collect(ppoly(a,na));
+end

FOTF Toolbox/@ppoly/ppoly.m

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+% ppoly - class definition of a ppoly object
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+classdef ppoly
+   properties, a, na, end
+   methods
+     function p=ppoly(a,na)
+     if nargin==1
+        if isa(a,'double'), p=ppoly(a,length(a)-1:-1:0);
+        elseif isa(a,'ppoly'), p=a;  
+        elseif a=='s', p=ppoly(1,1); end
+     elseif length(a)==length(na), p.a=a; p.na=na;
+     else, error('Error: miss matching in a and na'); end
+end, end, end

FOTF Toolbox/@ppoly/uminus.m

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+function p1=uminus(p)
+% uminus - find -p
+%
+%    p1=-p
+%
+%   p, p1 - ppoly objects
+
+% Copyright (c) Dingyu Xue, Northeastern University, China
+% Last modified 18 May, 2022 
+   p1=ppoly(-p.a,p.na);
+end