MFC is filled with lines like this:

where the precision is declared via kind(0d0).
We also have a ton of this

where inline constants have precision declared in a "hard-coded" way.

What is better is declaring a separate constant that we can change as needed, like this
example, though there are many others.

A fix for this issue would remove all cases of 0d0 and kind(0d0) and replace them with a constant declared in the common/ directory. I think this is a suitable task for @anshgupta1234 .

I realize one can force precision via compiler variables, but I believe we should avoid this because there is an established language standard.