A Short Error Message (explanation wanted)

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suusie
Posts: 30
Joined: Mon May 21, 2012 4:16 am

A Short Error Message (explanation wanted)

Post by suusie »

Dear Sir/Madam:

I sometimes had a short error message which might be related to the method of modeling (connection of nodes by elements, material properties, and definition of geometric transformation, etc...).

I am just wondering if you can briefly explain the error message below (as an example among other similar error messages that I got), so that I can eliminate this kind of error message more efficiently:

ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (1710, -9.09463e-013)

Best regards,
Sue.
fmk
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Re: A Short Error Message (explanation wanted)

Post by fmk »

in the solution process the solver determined that the matrix is NOT symmetric positive definite .. how has the matrix become such:?
1) not enough constraints (think sdof problem with 0 constraints)
2) the model has developed a mechanism, (think single dof problem with 0 tangent after yield)
3) the model or parts of it have become unstable (think a single dof problem with a negative slope ater yield)
4) the matrix is ill-conditioned.
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