Modify dmequad semantics in WidebandTimingModel to match MeasurementNoise

[vallis]

• Modified definition of log10_dmequad in WidebandTimingModel (now matches T2EQUAD);
• merged selection masks for dmefac and dmequad;
• allowed setting log10_dmequad=None;
• rationalized code in small ways.

[codecov[bot]]

Codecov Report

Merging #324 (a81dfbb) into master (2fb1bf3) will increase coverage by 0.03%. The diff coverage is 85.71%.

Additional details and impacted files

[](https://codecov.io/gh/nanograv/enterprise/pull/324?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv) ```diff @@ Coverage Diff @@ ## master #324 +/- ## ========================================== + Coverage 88.33% 88.37% +0.03% ========================================== Files 13 13 Lines 3010 3011 +1 ========================================== + Hits 2659 2661 +2 + Misses 351 350 -1 ``` | [Impacted Files](https://codecov.io/gh/nanograv/enterprise/pull/324?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv) | Coverage Δ | | |---|---|---| | [enterprise/signals/selections.py](https://codecov.io/gh/nanograv/enterprise/pull/324/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv#diff-ZW50ZXJwcmlzZS9zaWduYWxzL3NlbGVjdGlvbnMucHk=) | `90.41% <ø> (ø)` | | | [enterprise/pulsar.py](https://codecov.io/gh/nanograv/enterprise/pull/324/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv#diff-ZW50ZXJwcmlzZS9wdWxzYXIucHk=) | `92.05% <75.00%> (-0.18%)` | :arrow_down: | | [enterprise/signals/gp\_signals.py](https://codecov.io/gh/nanograv/enterprise/pull/324/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv#diff-ZW50ZXJwcmlzZS9zaWduYWxzL2dwX3NpZ25hbHMucHk=) | `90.68% <88.23%> (+0.37%)` | :arrow_up: | ------ [Continue to review full report at Codecov](https://codecov.io/gh/nanograv/enterprise/pull/324?src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://codecov.io/gh/nanograv/enterprise/pull/324?src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv). Last update [2fb1bf3...a81dfbb](https://codecov.io/gh/nanograv/enterprise/pull/324?src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=nanograv).