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 

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From: Mark Adams <mfadams@lbl.gov>
Sent: Wednesday, December 20, 2023 2:48 AM
To: Shatanawi, Sawsan Muhammad <sawsan.shatanawi@wsu.edu>
Cc: petsc-users@mcs.anl.gov <petsc-users@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@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