Robuta

https://docs.mfem.org/4.3/ex3_8cpp.html
mfemexamplescppfilereference
https://software.llnl.gov/news/2020/11/02/mfem-4.2/
MFEM is a lightweight, general, scalable C++ library for finite element methods. Its goal is to enable high-performance scalable finite element discretization...
mfemreleasedllnlsoftwareportal