RouthCriteria.m

classdef RouthCriteria
    properties
        rowz;
        itterations;
        system;

    end
    methods
        function generate_rows(obj)
            new_rows=obj.rowz;
            append_row=zeros(1,height(new_rows));
            itter= (obj.itterations)-2;
            y=width(new_rows);
            order=strings(1:obj.itterations);

            append_row=zeros(itter,width(new_rows));
            for j=1:obj.itterations  %%set the indexes of table i.e s^4 s^3 etc
                pow=j-1;
                order(j)=sym('s')^string(pow);
            end


            for i=1:itter  %%excute routh criteria
                try
                    for p= 1:y

                        mul1=new_rows((i+1),p);
                        mul2=new_rows((i),(p+1));
                        mul3=new_rows((i),(p));
                        mul4=new_rows((i+1),(p+1));
                        num2=(mul1*mul2)-(mul3*mul4);
                        new = num2/new_rows((i+1),p);
                        append_row(i,p)=new;



                    end

                catch
                    append_row(i,p)=0;
                end

                %%special case when a whole row equal zeros take derivative
                %%aux
                if 1/poly2sym(append_row(i,:))==inf && i~=obj.itterations-2
                    aux_list=[];
                    counter=1;
                    for k=1:length(new_rows)
                        aux_list(counter)=new_rows(end,k);
                        aux_list(counter+1)=0;
                        counter=counter+2;
                    end
                    aux_list=aux_list(1:length(aux_list)-1);
                    maxlen=max(height(new_rows));
                    aux_sys =poly2sym(aux_list);
                    aux_sym= fliplr(coeffs(diff(aux_sys)));
                    aux_sym(end+1)=0;

                    append_row(i,:)=aux_sym;
                end
                %%special case when a first element is zero ,, make it
                %%epcilon
                if p ==1 && append_row(i,1)==0 && i~=obj.itterations-2
                    append_row(i,1)=[0.0001];
                end

                new_rows=[new_rows;append_row(i,:)];




            end
            %%setup table
            index=[flip(order(1:obj.itterations))];
            Routh_table=table(transpose(index),new_rows);
            disp(Routh_table)
            %%count sign changes to check stability
            count=0;

            for k=1:height(new_rows)
                try
                    if new_rows(k,1)<0  && new_rows(k+1,1)>0
                        count=count+1;

                    end
                catch
                    if new_rows(k,1)<0 && k==height(new_rows) && new_rows(k-1,1)>0
                        count=count+1;
                    end
                end




            end
            if count>0

                fprintf("system is unstable with %d real positive poles",count)
            else
                fprintf("system is stable")

            end
            try
                rlocus(obj.system)
            catch
            end
        end


    end
end