What s the meaning of this error in matlab?

Hi

I have a problem in solving 3 coupled equation that i used MOL to solve them.These are equations

and initial condition are zero for all equations.

i descritized equations in radius and lenght and convert them to a system of odes.but an error accured in MATLAB.

THIS IS THE ERROR:

Error using daeic3 (line 132)
This DAE appears to be of index greater than 1.

Error in ode15s (line 313)
    [y,yp,f0,dfdy,nFE,nPD,Jfac,dMfac] = daeic3(odeFcn,odeArgs,tspan,htry,Mtype,Mt,Mfun,...

Error in massmain (line 47)
[t,y]=ode15s(@massfunc,t,y,options)

I attached my program.

i cant run this program for a month.

please help me.

thanks.

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/102944-what-is-the-meaning-of-this-dae-appears-to-be-of-index-greater-than-1-using-ode-solvers-for-solvin

Sometimes it is a boundary condition problem:

http://www.mathworks.com/matlabcentral/answers/60041-trying-to-use-pdepe-function-to-solve-a-1-d-diffusion-problem-i-am-getting-a-strange-error

Answer 2

[Leon Heile]

solutions? have the exact same problem

Answer 3

[Minjun Bae]

Hi, have you handled this issue?

I am trying to use PDE toolbox, and have the exact same problem. ;(