# What does this error report mean

**URL:** https://community.freefem.org/t/what-does-this-error-report-mean/3923
**Category:** General Discussion
**Created:** [May 19, 2025, 6:49am UTC](https://community.freefem.org/t/what-does-this-error-report-mean/3923 "2025-05-19T06:49:40Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![zxss](https://avatars.discourse-cdn.com/v4/letter/z/bc8723/32.png) [@zxss](https://community.freefem.org/u/zxss)
#### Post date: [May 19, 2025, 6:49am UTC](https://community.freefem.org/t/what-does-this-error-report-mean/3923/1 "2025-05-19T06:49:40Z")

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Dear all,

I am now updating my 2D navier stokes equation with moving boundary to 3D, here is the code  
[Parallel\_3d\_NS\_moving.edp](https://community.freefem.org/uploads/short-url/a1aRqoRdfY7sgJw0cTORUwGt7Va.edp) (4.4 KB)  
[Th.mesh](https://community.freefem.org/uploads/short-url/hl1KuTNPdJgYQEIPqTJOdzkPu0I.mesh) (734.3 KB).  
However, I meet a error report when I run it for some time as

 ![Screenshot from 2025-05-19 07-45-14](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/7/71c77f01899cda9a3c07b366aed4b5d8e723b787.png)  
I don’t know what does it mean. Does anyone encounter similar error and know why it occurs?

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### Author: ![zxss](https://avatars.discourse-cdn.com/v4/letter/z/bc8723/32.png) [@zxss](https://community.freefem.org/u/zxss)
#### Post date: [May 19, 2025, 4:10pm UTC](https://community.freefem.org/t/what-does-this-error-report-mean/3923/2 "2025-05-19T16:10:01Z")

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What’s more, I find a interesting result when I use “-pc\_type hypre”

 ![Screenshot from 2025-05-19 17-05-18](https://canada1.discourse-cdn.com/flex030/uploads/freefem/original/2X/4/4739d90265179228e67119a39c1ba1a8ebba955c.png)  
when it doesn’t converge fistly time, it can calculate again automatically. What is the mechanism behind?

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### Author: ![aszaboa](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/aszaboa/32/2918_2.png) [@aszaboa](https://community.freefem.org/u/aszaboa)
#### Post date: [May 19, 2025, 10:39pm UTC](https://community.freefem.org/t/what-does-this-error-report-mean/3923/3 "2025-05-19T22:39:19Z")

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I do not know the the exact issue, but I am not sure you can use `convect` when running FreeFEM with PETSc in parallel. Maybe looking at the solution can also provide the insight.

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### Author: ![zxss](https://avatars.discourse-cdn.com/v4/letter/z/bc8723/32.png) [@zxss](https://community.freefem.org/u/zxss)
#### Post date: [May 20, 2025, 6:02am UTC](https://community.freefem.org/t/what-does-this-error-report-mean/3923/4 "2025-05-20T06:02:24Z")

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Yes, after reading this post [Convect( ) in parallel - #2 by prj](https://community.freefem.org/t/convect-in-parallel/1270/2). I know that using ‘convect’ inside a ‘varf’ will generate wrong results for high timesteps. But it seems work at small time step as this post [Convect( ) in parallel - #6 by mojtaba.barzegari](https://community.freefem.org/t/convect-in-parallel/1270/6) shows. Anyway, I will change ‘convect’ in ‘varf’ with ‘convectParallel’ to see what will happen.  
Many thanks for your reply.