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Undefined value found in the stiffness matrix.
Posted Nov 10, 2012, 4:28 p.m. EST 2 Replies
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Hi I am Getting Following error when I am trying to solve Mosfet model in comsol
Undefined value found.
- Detail: Undefined value found in the stiffness matrix.
.There are 9 equations giving NaN/Inf in the matrix rows for the variable mod1.phi0
. at coordinates: (1.85106e-007,-3.45295e-007), (7.68991e-008,-2.18897e-007), (1.31003e-007,-2.82096e-007), (8.2885e-009,-3.71345e-007), (9.66972e-008,-3.5832e-007), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns.
thanks and regards
Pavan Naik
Undefined value found.
- Detail: Undefined value found in the stiffness matrix.
.There are 9 equations giving NaN/Inf in the matrix rows for the variable mod1.phi0
. at coordinates: (1.85106e-007,-3.45295e-007), (7.68991e-008,-2.18897e-007), (1.31003e-007,-2.82096e-007), (8.2885e-009,-3.71345e-007), (9.66972e-008,-3.5832e-007), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns.
thanks and regards
Pavan Naik
2 Replies Last Post Dec 22, 2014, 4:31 a.m. EST
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Posted:
1 decade ago
Hi
it mens exactly what is written: some values are mising, ...
the difficulty, I agree, is to identify which values ;)
often it's some material properties, perhaps you have some surface physics and you need a "boundary" material duplicated, or different, from another "domain" material definition; or it's a BC missing.
Have you checked which dependent variables you are solving for ? and do all of them have enough BC values, in absolute (Dirichlet) and or flux (Neumann) and 2 if 2nd order derivatives are involved
--
Good luck
Ivar
it mens exactly what is written: some values are mising, ...
the difficulty, I agree, is to identify which values ;)
often it's some material properties, perhaps you have some surface physics and you need a "boundary" material duplicated, or different, from another "domain" material definition; or it's a BC missing.
Have you checked which dependent variables you are solving for ? and do all of them have enough BC values, in absolute (Dirichlet) and or flux (Neumann) and 2 if 2nd order derivatives are involved
--
Good luck
Ivar
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Posted:
10 years ago
Thank you Ivar, I found my problem in the boundary condition to be incorrect input.