Example using Coarsen.construct to split map into regions

[TomNicholas]

I realised there is very little documentation on Coarsen.construct, so I added this example.

Unsure whether it should instead live in the page on reshaping and reorganising data though, as it is essentially a reshape operation. EDIT: Now on the reshape page

• Closes #xxxx
• Tests added
• User visible changes (including notable bug fixes) are documented in whats-new.rst
• New functions/methods are listed in api.rst

cc @jbusecke @paigem

[dcherian]

Unsure whether it should instead live in the page on reshaping and reorganising data though, as it is essentially a reshape operation.

This would be good IMO

[dcherian]

Thanks @TomNicholas

LGTM as long as it renders nicely.

[TomNicholas]

LGTM as long as it renders nicely.

It renders nicely locally, but any idea why the RTD build fails so opaquely?

[dcherian]

/home/docs/checkouts/readthedocs.org/user_builds/xray/checkouts/7192/doc/whats-new.rst:2999: WARNING: undefined label: comput.coarsen
/home/docs/checkouts/readthedocs.org/user_builds/xray/checkouts/7192/doc/whats-new.rst:3054: WARNING: undefined label: comput.coarsen

We fail in warnings in RTD