eldo_user

Analyzing Simulation Results
Diagnosing Convergence and Performance Issues
Diagnosing Convergence and Performance
Issues
A set of diagnostics are available through the -diagmode command line argument to help you
understand why a circuit does not behave as expected, or takes more time than expected to
simulate.
Diagnostics activated are:
Non-Convergence Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
Time Step Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
Performance Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380
Non-Convergence Analysis
The analysis of non-convergence issues is enabled with the -diagmode conv command line
argument. When Eldo stops because of a non-convergence a file is generated named
.noconv, used as an input for the convergence analysis (where filename is either the
netlist name or the name specified by the -out argument).
This functionality is only available with Eldo Classic.
Note
It is recommended to use the -outpath command line argument in
conjunction with this command as many new files might be generated during the new
simulation.
The non-convergence file generated, .noconv, contains:
• Time at which the non-convergence occurred.
• Cause of the non-convergence (Newton or LTE).
• List of nodes/devices for which the residual current is too high (Newton).
• List of nodes for which the bias is changing too much from one iteration to another
(Newton).
Based on this information Eldo automatically generates plots of the nodes, for Voltage (V) and
current contributions (IN), for the devices connected to the detected nodes. Doing so you can
monitor how the voltage evolves on those nodes and monitor the total current contributions of
each device connected on those nodes. All the automatic plots generated are referenced in a new
folder of the simulation database named DEBUG_.
For example:
Eldo® User's Manual, 15.3 377