[petsc-users] Help with Integrating PETSc into Fortran Groundwater Flow Simulation Code

[Mark Adams]

Did you set preallocation values when you created the matrix?
Don't do that.

On Wed, Dec 20, 2023 at 9:36 AM Shatanawi, Sawsan Muhammad <
sawsan.shatanawi at wsu.edu> wrote:

> Hello,
>
> I am trying to create a sparse matrix( which is as I believe a zero
> matrix) then adding some nonzero elements to it over a loop, then
> assembling it
>
> Get Outlook for iOS <https://aka.ms/o0ukef>
> ------------------------------
> *From:* Mark Adams <mfadams at lbl.gov>
> *Sent:* Wednesday, December 20, 2023 2:48 AM
> *To:* Shatanawi, Sawsan Muhammad <sawsan.shatanawi at wsu.edu>
> *Cc:* petsc-users at mcs.anl.gov <petsc-users at mcs.anl.gov>
> *Subject:* Re: [petsc-users] Help with Integrating PETSc into Fortran
> Groundwater Flow Simulation Code
>
>
> *[EXTERNAL EMAIL]*
> I am guessing that you are creating a matrix, adding to it, finalizing it
> ("assembly"), and then adding to it again, which is fine, but you are
> adding new non-zeros to the sparsity pattern.
> If this is what you want then you can tell the matrix to let you do that.
> Otherwise you have a bug.
>
> Mark
>
> On Tue, Dec 19, 2023 at 9:50 PM Shatanawi, Sawsan Muhammad via petsc-users
> <petsc-users at mcs.anl.gov> wrote:
>
>> Hello everyone,
>>
>> I hope this email finds you well.
>>
>>  My Name is Sawsan Shatanawi, and I am currently working on developing a
>> Fortran code for simulating groundwater flow in a 3D system. The code
>> involves solving a nonlinear system, and I have created the matrix to be
>> solved using the PCG solver and Picard iteration. However, when I tried
>> to assign it as a PETSc matrix I started getting a lot of error messages.
>>
>> I am kindly asking if someone can help me, I would be happy to share my
>> code with him/her.
>>
>> Please find the attached file contains a list of errors I have gotten
>>
>> Thank you in advance for your time and assistance.
>>
>> Best regards,
>>
>>  Sawsan
>>
>>
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