OpenSees Applications

Which OpenSees to run on DesignSafe?

There are three main applications, each with its own use case.

• Sequential Application:

  1. OpenSees is the simplest application:

     • Regular OpenSees
       Single core and is easy to use.
       It’s your starting place and can easily meet most project needs.

• Parallel Applications:

  1. OpenSeesSP is the Single Parallel Interpreter application:

     • The single processor distributes a large model to the remaining processors for faster solution strategies.

     • This application allows you to run very large models with ease because it automates the model decomposition with no need for input from the user.

     • This application may not be available on OpenSeesPy

  2. OpenSeesMP is the Multiple Parallel Interpreters application:

     • It is the most versatile parallel application.

     • It runs all the processors in parallel, each executing the same script containing individual instructions for each processor.

     • This is the most powerful OpenSees application by giving the user full control of the job.

     • Two types of parallelization:

       1. Manual Model Decomposition (automated in OpenSeesSP).

       2. Distributed parametric analyses.

     • Improve efficiency with Load Balancing (inter-processor communication)

These applications are available in the TCL interpreter, as well as in the Python interpreter (OpenSeesPy). However, there are several ways to run OpenSeesPy in the parallel environment.
Running OpenSeesSP in OpenSeesPy requires some verification since it is environment-dependent. This is beyond the scope of this traning content.

Decision Matrix for OpenSees Applications

Model Size	Analysis Parameters	Sequential OpenSees	Parallel OpenSeesSP	Parallel OpenSeesMP
small–medium	none–few	✅ Recommended	🚩 Element Robustness	⏳ Extra time to set up the script
small–medium	many	⏳ Wait Time	🚩 Element Robustness	✅ Recommended
medium–large	none–few	⛔ Too Slow	✅ Recommended	✅ Recommended + ⚠️ Manual Scripting
medium–large	many	⛔ Too Slow	🚩 Element Robustness + ⛔ Too Slow	✅ Recommended + ⚠️ Manual Scripting
very large	none–few	⛔ Too Slow	✅ Recommended	✅ Recommended + ⚠️ Manual Scripting
very large	many	⛔ Too Slow	✅ Recommended 1 analysis/job	✅ Recommended + ⚠️ Manual Scripting

Legend:

• ✅ Recommended solution

• ⏳ Additional wait time due to HPC queue makes it a weak solution

• 🚩 Requires ensuring element robustness in OpenSeesSP (weak solution)

• ⚠️ Manual domain decomposition requires extra scripting effort

• ⛔ Additional run time due to single-threaded execution makes it a bad solution