Running FasterCap
Run Menu dialog box
The FasterCap Run Menu dialog box contains many options. In the following, the different options will be explained in detail, with reference to the Run Menu figure here below.
Input file name
This information is mandatory to run the simulation. This is the file name of the root file containing FasterCap input data (see FasterCap Input Files for more information about input files). The file name can also include path information, or you can browse for the file using the dedicated button.
Automatic settings
For most simulations, you can rely on FasterCap to automatically adjust the settings to converge to a solution within the given error tolerance.
In this case, you must check the box 'Automatically calculate settings' and enter a value into the 'Stop when relative error is lower than (-a)' field. This value is the desired residual tolerance on the error, calculated as the Frobenius norm of the weighted capacitance matrix difference (this is one of the standard ways to measure the difference between two matrices).
For example, a value of 0.01 means a residual error of 1%, a value of 0.05 a resudual error of 5%, and so on.
You can also select if FasterCap should make an automatic choice of the preconditioner, to try to accelerate the solution (by performing less iterations); in this case, you must check the box 'Automatic preconditioner usage (-ap)'. There are reasons why you would not want the preconditioner to be automatically selected, in this case uncheck the box and specify the type of preconditioner you want to use in the 'Common settings' group (see below).
Manual settings
If you want absolute control over your simulation, you can force FasterCap to follow the manual settings.
In this case, you must NOT check the box 'Automatically calculate settings' and enter a value in all the fields of this section.
- 'Mesh relative refinement value (-m)' controls the maximum refinement allowed on the input geometry. The lower the value, the more accurate the result, but simulation time will increase accordingly.
- 'Gmres iteration tolerance (-t)' controls the error below which the iterative solver will stop. This controls the relative error of the solution.
For example, a value of 0.01 means a residual error of 1%, a value of 0.05 a resudual error of 5%, and so on.
Remark: the accuracy of the capacitance value that can be obtained with this parameter is limited by the refinement level of the mesh. If the mesh is too coarse, lowering this number will give no benefit.
Common settings
General Options
These options can always be selected or not, independently from automatic or manual settings.
- 'Output refined geometry in FastCap2 format (-o)' dumps the FasterCap mesh geometry at the end of the refinement phase to a set of files, in the same directory of the input file. These files are in FastCap2 compatible format, so can be input to FastCap2 and to FastModel. This option is useful for instance for comparison of FasterCap results with FastCap2 results, or to see the refined mesh in FasterCap. Please be aware however that for high levels of refinement the output files can be huge, and can also take some time to be stored on the mass memory device.
The main file is named as the specified input file, with the extension '_ref.lst'. All the other input files are referenced inside this main file.
- 'Dump input geometry in FasterCap format and stop (-oi)' dumps the input geometry just after finishing reading it (i.e. with no refinement) to a set of files, in the same directory of the input file, and then stops. These files are in FasterCap format, and are a dump of the internal FasterCap representation; for instance, all panels are already translated. This option is mainly useful for checking the input file correctness, e.g. to see if FasterCap flags any error, or to flatten a hierarchical set of input files.
The main file is named as the specified input file, with the extension '_dump.lst'. All the other input files are referenced inside this main file.
- 'Dump Gmres residual at each iteration (-r)' causes FasterCap to dump at each iteration of the iterative solver the relative residual GMRES error near the iteration number.
- 'Output capacitance matrix to file (-e)' outputs the resulting capacitance matrix to file in comma-separated value (CSV) format. The capacitance matrix file is named as the specified input file, with the extension '.csv'.
- 'Dump charge densities in output file (-c)' dumps a set of FasterCap mesh geometries containing charge densities information. One set of files is output, in the same directory of the input file, for each conductor specified. These files are in FastModel compatible format, so they can be loaded into FastModel for charge density visualization. Please be aware however that for high levels of refinement the output files can be huge, and can also take some time to be stored on the mass memory device.
The main files are named after the specified input file, merged with the conductor name, with the extension '.lst'. All the other input files are referenced inside the main files.
- 'Dump detailed time and memory information (-m)' causes FasterCap to dump in the output text detailed time and memory information for each of the phases in the solution.
- 'Verbose output (-v)' instructs FasterCap to dump in the output text verbose information about what it is doing. While this is not normally useful, it can assist the troubleshooting in case of errors reported by FasterCap, by providing additional information.