Detailed IPOPT Log in ipopt_v2

[mrmundt]

Fixes #548, #728 , IDAES/idaes-pse#92

Summary/Motivation:

There is a utility wrapper in parmest that gathers helpful data from the IPOPT log that has never been promoted to a "real world citizen." This PR replaces the need for that in ipopt_v2 by parsing the output and storing important data by default on the Results object.

NOTE: This PR contains #3576 so that one needs to be merged first.

Changes proposed in this PR:

• Update IPOPT parsing logic to capture iterations, various final scaled/unscaled results, the full solver log, etc.
• Update tests to ensure that we are actually capturing the output
• Fix a really sneaky bug that only appeared on older Python versions in Windows that stopped output from being captured

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[michaelbynum]

A couple minor comments. Yay for improved type hints!

[michaelbynum]

I'm confused. What type of object does results.extra_info.get("iteration_log") return? From below, I thought it would be a list.

[mrmundt]

Correct - it's a list. (It can be a very long list, because it captures all of the iterations. See IDAES/idaes-pse#92 (comment))

EDIT: To be clear, the remainder of parsed_output_data by this point is a dictionary with complementarity, constraint_violation, final_scaled_results, iteration_log, etc. iteration_log is the only thing that I am setting to ADVANCED_OPTION because it can be a lot to print out when running *.display().

[michaelbynum]

I'm just confused about how it has the _visibility attribute...

[mrmundt]

Oh, because it's an implicitly declared ConfigValue.

[michaelbynum]

Oh, is there a copy of the log parsing code in parmest that needs to be removed?

[mrmundt]

Oh, is there a copy of the log parsing code in parmest that needs to be removed?

I'm hesitant to remove anything from parmest because I don't know how it's being used outside of Pyomo (e.g., it might be "the thing" that people are using to parse IPOPT output in other places). I figure it's something we can either (a) leave because it does no harm or (b) remove in the future with a fair deprecation warning.