Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Failed to evaluate variable Jacobian problem in a stationary & time dependent problem

Please login with a confirmed email address before reporting spam

Hello,

I'm new to Comsol and I'm trying to solve a 2D problem in which electric potential calculation and diffusion are involved, in a rectangular domain in which a portion is defined, as intial condition, as an high concentration region (hence high conductivity).

My workflow is as follows: I solve the electrostatic problem with "Electric current" with a stationary solutor (stationary solver) first step of the solver. Then the solutor has a second time dependent step in which the diffusion equation is solved (I use pde module). The electric field is used as an input for the diffusion parameters.

Every time I try to solve I get:

Failed to evaluate variable Jacobian.
- Variable: ec.Ey
- Geometry: 1
- Domain: 1

I cannot understand why? The software is capable to solve the problem when the sencond step of the solver and the related physics are disabled and this probably means that the solver is able to compute the potential solution.

I'll thank you in advance for your help

Stefano

2 Replies Last Post 18 févr. 2011, 09:35 UTC−5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 18 févr. 2011, 08:57 UTC−5
Hi

you should recheck all the definitions used for Ey, or to create it, probably you have something mistyped in one of the BC's or the initial conditions

--
Good luck
Ivar
Hi you should recheck all the definitions used for Ey, or to create it, probably you have something mistyped in one of the BC's or the initial conditions -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 18 févr. 2011, 09:35 UTC−5
Thank you for your help Ivar, I'll check
Thank you for your help Ivar, I'll check

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.