dlogX -> logdX

[williamjameshandley]

Description

This has come up in the past, but explicitly today with margret, the notation dlogX is unfortunate, in that it is quite definitely wrong. In the spirit of logL, it should really be logdX since it is the log of small volume shell dX. This makes expressions make a little more sense.

This is a breaking change (albeit a minor one -- very few users will be using this underlying code), so it should be merged before 2.0.0 release. I have added a helpful error to the old notation.

Checklist:

• I have performed a self-review of my own code
• My code is PEP8 compliant (flake8 anesthetic tests)
• My code contains compliant docstrings (pydocstyle --convention=numpy anesthetic)
• New and existing unit tests pass locally with my changes (python -m pytest)
• I have added tests that prove my fix is effective or that my feature works
• I have appropriately incremented the semantic version number in both README.rst and anesthetic/_version.py

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (98a4eb2) 100.00% compared to head (d2e12f2) 100.00%.

Additional details and impacted files

@@            Coverage Diff            @@
##            master      #306   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           30        30           
  Lines         2665      2667    +2     
=========================================
+ Hits          2665      2667    +2     

Impacted Files	Coverage Δ
anesthetic/_version.py	100.00% <100.00%> (ø)
anesthetic/samples.py	100.00% <100.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[lukashergt]

This definitely clears up the notation, very nice. Should we add a check for logdX's existence?

[lukashergt]

Great, please squash and merge.