Speed of Iteration and convergence failure

Hi,sorry for bothering you!
Now I am working on 2D-LGad s.When I initial the solution,the speed of interation was very slow.I found that the step of interation was short.And that results in “Convergence failure”.I was wondering why.
p.s.I notice we solve by the way of LU.Can we use the way named “jacobi” so we can control the length of step.
Thank you!!!

Hi,

My first suggestion is to try extended precision:

``````devsim.set_parameter(name = "extended_solver", value=True)
devsim.set_parameter(name = "extended_model", value=True)
devsim.set_parameter(name = "extended_equation", value=True)
``````

It is possible that the solution is good enough for an initial guess to the drift diffusion simulation. You can then adjust the `relative_error` and `absolute_error` so that the Potential only simulation finishes.

There is no Jacobi method implemented. There is a gmres option for the iterative solver, but it has not been extensively tested

``````solve(solver_type="iterative"
``````

there is also a custom solver option which involves writing code in python to implement new solvers. it is being used to implement the new UMFPACK direct solver

Hi!
Thank you for your constructive suggestions.It can work very well now.
I have another problem.It’s about capacitance.
According to my understanding，we solve capacitance by virtual circuits.And we create a node ,which can be voltage source.But I can’t understand the difference between"value"and “acreal”.Does value refer to the modulus of the voltage expressed as an imaginary number?

ps：And when I change acreal ,it always shows me this problem.

If I change v,nothing changed.

I am wondering why.
I’m sorry to bother you a lot.I beg your pardon if there are some stupid questions

There is no need to apologize. There are no stupid questions. I will be able to look more at your question this weekend. If you haven’t already, please look at this forum as well as the bjt report on GitHub.

Please note that you cannot change the number of circuit nodes after the first circuit analysis has been completed. If this is needed, I can change the program.

value is the magnitude of the dc voltage. acreal is the magnitude of a small signal perturbation. You then need to do a solve of type “ac” with a specified frequency. Please checkout the bjt example and let me know if you have any questions.

Thank you for your reply.Now it can work very well.I can use ‘devsim.circuit_alter(name=‘V1’, param=‘acreal’, value=0-v)’ to achieve my goal.Thank you very much!!!

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