Using the Simulator Performance Slider
Use the slider control in the Simulation Parameters dialog box to improve transient simulator performance by influencing the pivoting algorithm. The slider only influences the network solver; it has no effect on components that are not using the analog solver, such as state machines and digital systems. The slider is enabled if the Automatic check box in the Performance sub-section of the dialog box is cleared. Moving the slider to the left or to the right biases the pivoting algorithm toward partial or complete pivoting. At the extreme left slider position, the simulator uses purely diagonal pivoting; while at the extreme right slider position, the simulator uses purely complete pivoting.
The default position has been determined empirically to be the most effective for the largest variety of systems. In cases where the simulation fails to converge, or the initial solution is incorrect or not found, changing the slider position may be helpful.
Changing the slider position
Use the slider to improve inaccurate or slow simulations. You can also customize simulator performance to best fit the specific application domain and the systems to be simulated.
These guidelines determine the ideal slider position:
Partial Pivoting
- Typically yields a faster simulation.
- May lead to an inaccurate solution (which may lead to poor performance).
Systems with the following characteristics give better simulation results with partial pivoting:
- Small systems (<100 components) with symmetric structure.
- SML models usually contribute to a symmetric structure.
Complete Pivoting
- Typically gives more accurate results.
- Slower performance (as compared to partial pivoting) if the system does not have characteristics specifically suited for complete pivoting.
Systems with the following characteristics give better simulation results with complete pivoting:
- Medium to large systems (>100 components) with
highly non-symmetric structure.
Note:
VHDL-AMS models (and other non-SML models) usually contribute a non-symmetric structure.
- Systems with widely varying component values. For example, a system with some zero-valued resistances and some 10M Ohm resistances.