FEST-3D vs ngspice

FEST-3D is a Fortran 90 finite-volume computational fluid dynamics solver for Navier–Stokes flow problems on structured grids, developed for aerodynamics. It handles incompressible and compressible flows, including inviscid, laminar, transitional and turbulent cases. Users can select among flux schemes, reconstruction methods, time-integration options, turbulence models and transition models. MPI distributes computations across processors on one or more machines. The solver is free and open source under the GNU General Public License version 3.0, with source available from GitHub. Its installation script supports Ubuntu/Debian, CentOS and macOS, while manual installation instructions cover Linux. Building requires a Fortran compiler, an MPI library, CMake and Make. Tutorials in a separate repository address verification cases such as a smooth bump, lid-driven cavity, flat plates and an airfoil. FEST-3D writes VTK or Tecplot output for separate visualization tools. Grid generation and post-processing are outside the solver, and the project notes its halt/stop condition does not work with MPI.

ngspice is a free, open-source simulator for electric and electronic circuits described as netlists. It handles analog, digital, and mixed-signal designs, with models for active, passive, analog, and digital elements; model parameters can come from collections, manufacturers, or foundries. Its SPICE compatibility supports PSPICE or LTSPICE device model parameters and netlists for discrete circuits. For mixed-signal co-simulation, it supports Verilog blocks compiled with Verilator and, since ngspice-44, VHDL blocks using GHDL. The OSDI/OpenVAF interface connects Verilog-A compact device models without requiring programming on the ngspice side. It can also be built as a shared library or DLL for another application to control. Listed integrations include KiCad, Autodesk Fusion, and Python interfaces such as PySpice. ngspice does not include schematic entry: input is through the command line or files. The stable download page offers source archives and Windows binaries; Linux users are directed to their distributor or source compilation, and the project's own macOS release is unavailable there.