# Problem when running the viscoelastic model？

**URL:** https://community.geodynamics.org/t/problem-when-running-the-viscoelastic-model/3809
**Category:** General
**Created:** [December 13, 2024, 4:03pm UTC](https://community.geodynamics.org/t/problem-when-running-the-viscoelastic-model/3809 "2024-12-13T16:03:25Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![yangxiao](https://yyz2.discourse-cdn.com/flex036/user_avatar/community.geodynamics.org/yangxiao/32/2323_2.png) [@yangxiao](https://community.geodynamics.org/u/yangxiao)
#### Post date: [December 13, 2024, 4:03pm UTC](https://community.geodynamics.org/t/problem-when-running-the-viscoelastic-model/3809/1 "2024-12-13T16:03:25Z")

</div>

Dear Sir,

I would like to ask why, when running the viscoelastic model, it works fine with 1 CPU, but when using more than 1 CPU, the following error occurs:mpinemesis: …/…/…/pylith-2.2.2/libsrc/pylith/materials/ElasticMaterial.cc:406: virtual PylithScalar pylith::materials::ElasticMaterial::stableTimeStepImplicit(const pylith::topology::Mesh&, pylith::topology::Field\*): Assertion `dtStable \> 0.0’ failed.  
[0]PETSC ERROR: ------------------------------------------------------------------------  
[0]PETSC ERROR: Caught signal number 3 Quit: Some other process (or the batch system) has told this process to end  
[0]PETSC ERROR: Try option -start\_in\_debugger or -on\_error\_attach\_debugger  
[0]PETSC ERROR: or see [http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind](http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind)  
[0]PETSC ERROR: or try [http://valgrind.org](http://valgrind.org) on GNU/linux and Apple Mac OS X to find memory corruption errors  
[0]PETSC ERROR: configure using --with-debugging=yes, recompile, link, and run  
[0]PETSC ERROR: to get more information on the crash.  
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------  
[0]PETSC ERROR: Signal received  
[0]PETSC ERROR: See [http://www.mcs.anl.gov/petsc/documentation/faq.html](http://www.mcs.anl.gov/petsc/documentation/faq.html) for trouble shooting.  
[0]PETSC ERROR: Petsc Release Version 3.10.2, Jul, 01, 2019  
[0]PETSC ERROR: /public1/home/t0s000462/xiaoy/Pylith/pylith-2.2.2-linux-x86\_64/bin/mpinemesis on a named ca0407.para.bscc by t0s000462 Fri Dec 13 22:02:19 2024  
[0]PETSC ERROR: Configure options --prefix=/home/brad/pylith-binary/dist --with-c2html=0 --with-x=0 --with-clanguage=C --with-mpicompilers=1 --with-shared-libra/public1/home/t0s000462/xiaoy/Pylith/pylith-2.2.2-linux-x86\_64/bin/nemesis: mpirun: exit 59  
/public1/home/t0s000462/xiaoy/Pylith/pylith-2.2.2-linux-x86\_64/bin/pylith: /public1/home/t0s000462/xiaoy/Pylith/pylith-2.2.2-linux-x86\_64/bin/nemesis: exit 1。  
Could you please help me understand why this happens? Thank you!