Enable posterior plots of added cbc parameters

The function construct_cbc_derived_parameters enables us to calculate various quantities for commonly used CBC quantities. This MR allows us to then plot the posteriors in the usual way by adding the new parameters into the list of search_parameter_keys, and also gives them latex labels in parameter_labels. In other words, the following will now create a two-d plot of chi_eff vs chi_p

result.construct_cbc_derived_parameters()
result.plot_corner(parameters=['chi_eff', 'chi_p'])

I agree that this is definitely functionality that we want, but I think there's a more general issue here that we could be going after.

For one thing, this is really a cbc thing which is in the core, I'd personally like to move this to the gw directory. What we want is some way to:

• enable plotting of any parameter in the posterior.
• have the result know about the latex labels for those parameters.

I think the first should currently be possible, although I could be wrong.

The second we may be able to get from the prior if the prior is a BBHPriorSet we should be able to take the latex labels from there.

@colm.talbot , I agree it would be good if this was more general. But given that this MR only adds to the existing functionality, I think it is sensible to merge this and as a separate issue fix the general problem.

approved this merge request

mentioned in commit 082798fb

merged