# Can Calculix run across multiple nodes?

**URL:** <https://calculix.discourse.group/t/can-calculix-run-across-multiple-nodes/1316>\
**Category:** Uncategorized\
**Created:** [November 4, 2022, 4:24pm UTC](https://calculix.discourse.group/t/can-calculix-run-across-multiple-nodes/1316 "2022-11-04T16:24:05Z")\
**Posts on this page:** 1\
**Showing post:** 6

<div class="post-metadata">

**Author:** ![umut](https://avatars.discourse-cdn.com/v4/letter/u/54ee81/32.png) [@umut](https://calculix.discourse.group/u/umut)\
**Post date:** [February 24, 2025, 1:45pm UTC](https://calculix.discourse.group/t/can-calculix-run-across-multiple-nodes/1316/6 "2025-02-24T13:45:42Z")

</div>

Dear All,

I’ve been trying to run coupled conjugate heat transfer (CHT) cases using CalculiX, OpenFOAM, and PreCICE on an HPC system. **My question concerns running CCX efficiently on an HPC** , both on a single node and across multiple nodes, for optimal performance.

For additional details, please check my post on the PreCICE forum: [How to run CCX on HPC](https://precice.discourse.group/t/precice-spack-installation-on-hpc-fails-with-python3-related-error/2319/6).

I successfully installed `precice_ccx` with its dependencies (along with SPOOLES, SPOOLES-MT) on the HPC—some via building from source and others using Spack. I ensured that everything is compiled with the same GCC and MPI versions. I was able to run coupled simulations using SPOOLES with the following SLURM script:

```auto
cd solid
export OMP_NUM_THREADS=50
export CCX_NPROC_EQUATION_SOLVER=50
taskset -c 64-127 ccx_preCICE -i solid -precice-participant Solid > log.ccx
cd ..

```

Although it reports running on 50 cores, the speed-up is lower than expected. (Please check my precice post for complete slurm script.)

### My questions:

1. How can I properly run CCX on an HPC using a SLURM script?
2. What is the best configuration or setup to achieve maximum speed-up (scalability) for CCX on an HPC?
3. How can I report execution time or clock time at each timestep?

I would greatly appreciate any guidance, suggestions, or examples from those who have tackled similar issues.

Sincerely,  
Umut

---

_[View the full topic](https://calculix.discourse.group/t/can-calculix-run-across-multiple-nodes/1316)._