|Re: Modifiers for Graphs? [message #656289 is a reply to message #656267]
||Thu, 24 February 2011 23:02
| Stefan Edlund
Registered: July 2009
modifiers, triggers and predicates are actually still kind of experimental features in STEM, hence there are some limitations. So no, you cannot create a modifier on a graph or model (can you send us a link to the doc so we can fix that?).
Actually, the way we envision you would turn off air transportation would be to create a modifier on the air transport edge inside the graph that controls the number of passengers arriving/departing at particular region daily. That would potentially require lots of modifiers to shutdown everything.
We've also been playing with the idea of a global air transport throttle parameter that you could turn to 0 to shutdown air transportation completely.
Here is a workaround if you really want to see what would happen if you shut down air transport after some number of days:
1. Run and log a simulation with a scenario containing all you air transportation graphs in it.
2. Create a new scenario just like the first one, but remove the air transportation graphs from it as well as any infector/inoculator
3. Create a new infector and inoculator using the log file you just generated from the first scenario. You can do this in the New Infector wizard, by checking the checkbox "Import from STEM log files". In the "Selected row", pick the day you want air transportation to shut down. Drag your new (multi-region) infector and inoculator into your new scenario and run and log the result.
So what does this do? It will initialize your new scenario to the exact state your first simulation was in the day you wanted to shut down air transportation. So by combining the log files from the first and second scenario you get the results you want. Observe that this does not work for model that has the Exposed state in it, like SEIR (we have no way of initializing that).
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