Project Meeting 2017.03.03 - ActivitySim/activitysim GitHub Wiki

Multiple Zone Systems Network LOS

  • Multi-zone network LOS engine prototype will be complete by COB Friday
  • See the Readme for running the example
  • All queries are vectorized and fast
  • Still working on the basic transit virtual path building (TVPB) query
  • Added an expressions file for specifying the TVPB utility
  • Budget will be spent by end of the week as well
  • @Wu review and test

Data Pipelining

  • Started working on data pipelining revisions, mainly support for restartable model runs
  • For example, we have a model with three sub-models A, B, and C. Yesterday we ran sub-models A, B, and C and the data store kept track of the fact that sub-models A, B, and C were run. Today when we run just sub-model C, ActivitySim first checks to make sure sub-models A and B were run and then it runs sub-model C.
  • Not using a new framework, but instead creating our own so it can work with orca
  • We are reducing our dependency on orca though, and also not abandoning it since that would be too expensive
  • Orca tables are being saved to the datastore as pandas data frames and then being wrapped as orca tables on I/O
  • @RSG will have more to share on our next call and draft a [Design | Data-Pipelining-and-Random-Number-Sequencing-Design] page

Random Number Sequences

  • Started working on as-stable-as-possible random number sequencing across scenarios, sample rates, etc.
  • This feature works in conjunction with the restartable data pipeline
  • A random number stream is attached to each household, person, and trip and then an offset is used for each sub-model that is run
  • For example, when the model runs sub-model A it uses the first offset, sub-model B uses the second offset, and sub-model C uses the third offset. If we restart the model run at sub-model C, it sees in the datastore that sub-models A and B were run and that offsets 1 and 2 have already been used as well.
  • The offsets are by sub-model run order, not sub-model name; this is more flexible and avoids requiring an a priori dictionary
  • @RSG will have more to share on our next call and draft a [Design | Data-Pipelining-and-Random-Number-Sequencing-Design] page

Governance

  • The project team had many comments on Joe's governance questions
  • Based on the comments, Joe drafted an ActivitySim Governance document based on the Apache Forrest governance document
  • Joe added the idea of Funders to the Project Management Committee (PMC)
    • For the time being, merit is funding
    • Committers can become PMC members once the funders get what they wanted
    • Funding is by organization
  • @Everyone please review and comment next week so @Joe can revise
  • Let's try for a draft governance plan on the wiki before the ActivitySim presentation at the TRB Planning Applications conference in May

Project management