Adams Car Package > Shared Material > Dialog Box - F1 Help > Solver Selection

Solver Selection

Settings → Solver → Selection            Shared Dialog Box
Sets the version of Adams Solver that your template-based product will use to run simulations.
Default Adams Solver:
■All template-based products - The FORTRAN (F77) version of Adams Solver is the default solver for all template-based analyses. The C++ (CXX) version of Adams Solver is the planned replacement for the Adams Solver (FORTRAN) in a future release, but is currently experimental.
■If you select the CXX version, your results and analysis run times may vary from the FORTRAN version. We've made the CXX solver available to you for your own experimentation.
The settings you choose using the dialog box apply only for the current session.
 
For the option:
Do the following:
Solver Selection
Select one of the following:
■F77 - Forces your template-based product to use the FORTRAN version of Adams Solver.
■CXX - Forces your template-based product to use the C++ version of Adams Solver.
The following options are available for Adams Solver (C++) only.
Pattern
Select a pre-defined pattern:
■default
Sets the pattern to the default for dynamic simulations. The default depends on the integrator selection. For WSTIFF and GSTIFF, the default pattern is TFFFTFFFTF, for HHT and Newmark, the default pattern is F.
■adaptive
Sets as PATTERN=F which turns on the adaptive Jacobian evaluation algorithm when using Adams Solver (C++). The evaluation of the integration Jacobian is then only done when needed, helping to improve run-time performance.
Tip: Selecting a pattern to request less frequent evaluations of the Jacobian matrix can decrease the computation time, decreasing the cost and improving the response time. However, infrequent evaluations could also be more expensive since the modified Newton-Raphson algorithm might require more iterations due to the slower convergence rates.
Thread Count
Adams Solver (C++)

Specify the number of parallel threads that Adams Solver (C++) uses when performing the simulation. The number of threads, n, must be an integer in the range of 1 to 128. The default value is 1. By executing multiple threads in parallel across multiple processors, Adams Solver (C++) can reduce the walltime required for a simulation.

Typically, the optimal number of threads is between N and 2N, where N is the number of processors (including virtual processors in the case of Pentium processors with HyperThreading enabled).
Note: The Intel® Pentium® 4 processor introduced a feature called Hyper Threading, where a single physical processor can support more than one logical instruction stream, simulating multiple logical processors on a single physical processor. For many applications and environments, this capability may offer performance improvements over non-Hyper Threading processors. If multiple analysis jobs are running concurrently, however, there may be performance degradations. If an installation determines this to be the case, hyper threading should be disabled. This can be done on a permanent basis through BIOS operations or, for Windows platforms, hyper threading may be disabled on a process by process basis using the “hyperthreads” keyword.