set_route_topology

set_route_topology
-net s_netName | -set dsetObj 
-pattern {steiner | trunk}

Description

Sets the route pattern for the given net or nets in the given set that determines how the nets will be routed.

By default, a Steiner minimum spanning tree topology is used, where a vertex can connect to any other vertex and steiner points can be added to decrease the length of the interconnection.

In trunk routing, some portion of the net, typically a preroute, is identified as a trunk. All other vertices are connected to the trunk. Only shapes in shape terms or in a cover macro are automatically designated as parts of the trunk. For shapes that do not meet this criteria but should be included, some additional processing is needed:

For shapes that are placed under routes, use convert_routing_shapes to convert them to shape terms.
```
convert_routing_shapes -to_special -set d_setOobj
```
For shapes that are placed under terminals or instance terminals, and not in shape terms or in a cover macro, use set_is_trunk to include them in the trunk.
```
set_is_trunk -set d_setObj
```

If trunk topology is specified and no trunk shapes are found, the route topology defaults to the Steiner topology.

The following figure compares the implementation of the two topology types for a net.

Arguments

`-net` s_netName
	Specifies the name of the net.
`-pattern` s_patternName
	Specifies the route pattern as one of the following:
	`steiner`	Permits each vertex to connect to any other vertex and allows steiner points to be added to decrease the length of the interconnection. This is the default.
	`trunk`	Connects all vertices to a trunk.
`-set` d_setObj	Sets the route pattern for nets in the set.

Examples

The following command sets netA to use the steiner topology.

set_route_topology -net netA -pattern steiner

Virtuoso Space-based Router Command Reference
Product Version IC23.1, September 2023