Merge cluster count covariance into TJPCov and create notebook demonstrating usage

[mattkwiecien]

Merge cluster count covariance into TJPCov and create notebook demonstrating usage

We have code that calculates cluster covariance (nxn covariance matrix) but it's separate from TJPCov and it doesn't read or write to a sacc file, this sprint will be oriented at merging it into TJPCov, driving the calculation by sacc file, and writing the covariance to a sacc file.

Contacts: Matt Kwiecien Day/Time: All day (approx. 7am-5pm PST), every day until finished Main communication channel: Slack GitHub repo: https://github.com/LSSTDESC/TJPCov Zoom room (if applicable):

Goals and deliverable

• Create a workflow to read from sacc file and determine if we calculate cluster covariance based on data within sacc file
• Complete PR that merges in the cluster nxn covariance into TJPCov
• Write the resultant covariance matrix to a sacc file
• Create a notebook that does the above 3 steps, annotated
• Improve numerical methods used in clusters covariance calculation

Resources and skills needed

• Python
• Basic knowledge of clusters
• Basic knowledge of covariance matrices
• Tutorial notebooks from Nelson: https://github.com/nrussofer/Cosmological-Covariance-matrices
• SACC tutorial notebook: https://github.com/LSSTDESC/sacc/blob/master/examples/SACC_for_clusters.ipynb

Detailed description

• Part of this work requires the TJPCov refactor to be completed (see #14 ), so helping with this issue may be a part of this.
• We also are interested in validating some of the old code used in the cluster covariance calculation