Complexity Field - 2025.2 English - UG906

Follow these steps to configure the Complexity field in the Report Design Analysis dialog box:

1. Enable complexity analysis:
   • Select the Complexity checkbox to report design netlist complexity.
   • This helps identify potential congestion based on connectivity density.
   • Equivalent Tcl option: -complexity
   Note: This option is compile-time sensitive, especially for large designs.
2. Set the hierarchical depth:
   • Select Hierarchical Depth to specify how many levels below the top cell to analyze.
   • To limit analysis and speed up processing, use the -cells option in the Advanced tab.
   • Equivalent Tcl option: -hierarchical_depth <arg>
3. Limit results using Rent coefficient threshold:
   • Use the Rent Greater Than option to filter the report to only include modules with Rent values above a threshold (default is 0.6).
   • Equivalent Tcl option: -rent_greater_than <arg>
4. Limit analysis based on instance count:
   • Use Instances Greater Than to ignore small modules unlikely to affect congestion. The default is 15,000.
   • Equivalent Tcl option: -instances_greater_than <arg>
   • Use Instances Lesser Than to exclude very large modules where congestion fixes might overly increase area. The default is 100,000.
   • Equivalent Tcl option: -instances_lesser_than <arg>
5. Filter based on average fanout:
   • Use Average Fanout Greater Than to skip modules with low average signal fanout. The default threshold is 3.0.
   • High Rent values combined with high average fanouts are more predictive of congestion.
   • Equivalent Tcl option: -av_fanout_greater_than <arg>