tracing requirements

[bstabler]

we're going to implement tracing in addition to logging (#87) since we need this feature to track down data and expression errors related to #81. What are the requirements for this functionality?

We discussed this on our call today and came up with the following list:

• easy to parse text format such as CSV
• easy to import into Excel since this is the tool most users will use for exploring the traced results
• maybe two outputs - one big log file like CT-RAMP does today so you can see relationships between sub-model data and expressions, and then a CSV file for each sub-model?
• user will specify one HH ID to trace
• output information will be similar to what CT-RAMP produces

[bstabler]

Team agrees tracing generally looks good - https://github.com/UDST/activitysim/wiki/Project-Meeting-2016.06.15

Here are a couple bugs/issues to fix:

• make sure all tables have headers
• make sure each model has a model design table with expressions and solved value

Some improvements for the future:

• joined views of tables for easier use
• add source table column to make manual joins of tables easier
  • create an external post-processor to create better reports for each model
  • take this version of tracing from raw data to beautiful reports
  • print labels instead of codes - such as person type 2 is worker; add print methods for data items

[toliwaga]

When dumping interaction_simulate model_design, it is kind of awkward to makes sense of the dumped dataframe when there are multiple persons in the traced households and they have different alternatives.

I think it might be more useful to create a separate csv file for each individual in the household so the alternative columns all mean the same thing. We can add a row to the file listing the alternative (d.g. TAZ) for each column.

I pushed a version that works like this hh-trace branch.

[bstabler]

the example outputs look good and maintain the requirement that they are easy to parse with a Python or R-type script. Please merge this into the master. Thanks.