singular Jacobian encountered in bvp4c

Hello,

I use "bvp4c" command for solving a ODE system,

I encounter the following problem:

??? Error using ==> bvp4c 
Unable to solve The collocation equations - a singular Jacobian encountered

Is there someone who knows a method or solution. My code is, as follows:

function [phi90,phivarrho,phiteta]=phiFn(a,S90,Svarrho,coeff)

c1=coeff(1); c2=coeff(2); c3=coeff(3); c4=coeff(4); c5=coeff(5); c6=coeff(6); c7=coeff(7); c8=coeff(8); c9=coeff(9);

options=[];

xinit1= linspace(-a/2,0);
xinit2=linspace(0,a/2);
xinit=[xinit1,xinit2];
yinit=[1 ;0; 0; -c7*c1; 1; 0; 0; -c7*c1];
solinit= bvpinit(xinit,yinit);

sol = bvp4c(@ode1,@BCs,solinit,options,S90,Svarrho,coeff)
xint=sol.x;
yint=sol.y;

phi90=yint(1,:);
phivarrho=yint(5,:);
phiteta=-(2*phi90+phivarrho);

     function odesys = ode1(x,y,region,S90,Svarrho,coeff)
          c1=coeff(1); c2=coeff(2); c3=coeff(3); c4=coeff(4);  
          c5=coeff(5); c6=coeff(6); c7=coeff(7); c8=coeff(8);  
          c9=coeff(9);
          switch region
              case 1    % x in [-a/2 0]
                  odesys = [ y(2);y(3);y(4);
                  (c6*c3*y(3)+c7*c3*y(1)+c9*c3*y(7)-c8*c2*y(3)-
                   c8*c4*y(7))/(-c5*c3+c1*c8);
                   y(6);y(7);y(8);(-c6*c3*y(3)-c7*c1*y(1)-
                   c9*c1*y(7)+c5*c2*y(3)+c5*c4*y(7))/(-c5*c3+c1*c8)];
              case 2    % x in [0 a/2]
                  odesys = [ y(2);y(3);y(4);
                 (c6*c3*y(3)+c7*c3*y(1)+c9*c3*y(7)-c8*c2*y(3)-
                  c8*c4*y(7))/(-c5*c3+c1*c8);
                  y(6);y(7);y(8);(-c6*c3*y(3)-c7*c1*y(1)- 
                  c9*c1*y(7)+c5*c2*y(3)+c5*c4*y(7))/(-c5*c3+c1*c8)];
          end
      end

      function res = BCs(YL,YR,S90,Svarrho,coeff)
        res = [YL(1,1)-S90;
              YR(1,1)-S90;
              YL(1,2)-S90;
              YR(1,2)-S90;
              YL(2,1);
              YR(2,1);
              YL(2,2);
              YR(2,2);
              YL(5,1)- Svarrho;
              YR(5,1)-YL(5,2);
              YL(5,2)-YR(5,1);
              YR(5,2)-Svarrho;
              YL(6,1);
              YR(6,1)-YL(6,2);
              YL(6,2)-YR(6,1);
              YR(6,2)];
      end

end

thank you

[Walter Roberson]

See http://www.mathworks.com/matlabcentral/answers/6369-bvp4c

Answer 1

[Zeynab Mousavi.K]

oooooooo i have the same problem with exactly the same error if you understood the answer please inform me and i will tell you any solution if i found

[Amir K Neghab]

Hi,

Have you found the error? I think so.

How can you solve the " Singular Jacobian Error"

[Walter Roberson]

Amir, did you follow the link in my Comment, and try the Singular option?

Answer 2

[Zachary]

Being that there are no 1/x terms in your odes we need to see your coeff function to determine if it contributes to the singular jacobian.