## CalculiX solver

Program's name: CalculiX solver

Available version(s):
CalculiX solver (pthreads) ·
CalculiX solver (OpenMP) ·

Programming language(s):
C ·
Fortran ·

Programming model(s):
OpenMP ·
Posix threads ·

Uses following algorithm(s):
Generalized minimal residual method (GRMRES) ·

Used in following discipline(s):
Computational Fluid Dynamics ·

CalculiX is a free three dimensional structural finite element analysis program. It supports linear and non-linear calculations of static, dynamic and thermal problems. The code is written in C and Fortran. Parallelization is achieved using the pthread programming model.

Our provided test case calculates the laminar flow of air through a bent pipe. At the heart of this calculation in each timestep an iterative scheme is employed, which in each iteration solves multiple non-symmetric systems of linear equations using a GMRES solver.

This is illustrated by the following pseudo code:

```
for(ts=0; ts<MAX_TIME_STEPS; ts++) {
for(n=0; n<MAX_TRANSIENT_ITERATIONS; n++) {
solve_momentum_conservation() // 3 linear systems solved with GMRES
solve_mass_conservation() // 1 linear system solved with GMRES
solve_energy_conservation() // 1 linear system solved with GMRES
}
}
```