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Division by zero

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Dear Experts,

I had a problem on my model. I'm trying to calculate the diffusion of electrons in gas, I'm using the drift-diffusion from plasma physics. Please see bellow the error:

Division by zero.
- Function: /
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.dd.Te@VDN$comp1.Ne
- Defined as: (((1/(unit_m_cf^3))*exp(comp1.Ne))*3)*((-(comp1.dd.en*2))/((comp1.dd.ne*3)^2))
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.dd.Dezz@VDN$comp1.Ne
- Defined as: ((((1/(unit_m_cf^3))*exp(comp1.Ne))*3)*((-(comp1.dd.en*2))/((comp1.dd.ne*3)^2)))*comp1.dd.muezz
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.dd.dflux_nez@VDN$comp1.Ne
- Defined as: (((-((1/(unit_m_cf^3))*exp(comp1.Ne)))*comp1.dd.Dezz)+((((((1/(unit_m_cf^3))*exp(comp1.Ne))*3)*((-(comp1.dd.en*2))/((comp1.dd.ne*3)^2)))*comp1.dd.muezz)*(-comp1.dd.ne)))*comp1.Nez
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.dd.gflux_nez@VDN$comp1.Ne
- Defined as: ((((1/(unit_m_cf^3))*exp(comp1.Ne))*comp1.dd.muezz)*d(comp1.dd.V,z))+((((-((1/(unit_m_cf^3))*exp(comp1.Ne)))*comp1.dd.Dezz)+((((((1/(unit_m_cf^3))*exp(comp1.Ne))*3)*((-(comp1.dd.en*2))/((comp1.dd.ne*3)^2)))*comp1.dd.muezz)*(-comp1.dd.ne)))*comp1.Nez)
Failed to evaluate expression.
- Expression: (((((1/(unit_m_cf^3))*exp(comp1.Ne))*comp1.dd.muezz)*d(comp1.dd.V,z))+((((-((1/(unit_m_cf^3))*exp(comp1.Ne)))*comp1.dd.Dezz)+((((((1/(unit_m_cf^3))*exp(comp1.Ne))*3)*((-(comp1.dd.en*2))/((comp1.dd.ne*3)^2)))*comp1.dd.muezz)*(-comp1.dd.ne)))*comp1.Nez))*dvol
Failed to evaluate Jacobian of expression.
- Expression: dvol*comp1.dd.gflux_nez
Failed to evaluate Jacobian of expression.
- Expression: (-comp1.dd.ne*comp1.Net*test(comp1.Ne)+comp1.dd.gflux_nex*test(comp1.Nex)+comp1.dd.gflux_ney*test(comp1.Ney)+comp1.dd.gflux_nez*test(comp1.Nez))*(dvol)

Please let me know if what could be the reasons for such problems.

Thank you in advance.


0 Replies Last Post Mar 14, 2017, 5:17 a.m. EDT
COMSOL Moderator

Hello Renato Negrao

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