Guide for new users and developers

For new users

see Installation notes for instructions for installing DALES on different systems / machines.
todo add WSL/Ubuntu in installation notes
The compiled program is in general not portable from one machine to another. For a new machine, compile again on that machine.
see Quirks for problems with specific systems and versions.

Parallel runs, especially with more than one node are not bitwise reproducible, because MPI does not guarantee bitwise reproducibility (probably the reduce operations which can happen in different order).
DALES runs that are even slightly different will diverge and become more and more different over time.

git and GitHub are used for DALES development. See this Software Carpentry course for git basics. Especially, learn about
- git clone (download DALES from github to your computer)
- branches (different "versions" of the DALES code, for example for developing a specific function)
- forking (make a copy of the DALES repository to your own GitHub account)
Avoid distributing DALES source code outside git, e.g. by email. It's hard to get the code back into git. If you want to send a version to someone else, make a new branch (in your own fork) for it, and send the link.
When changing the official version: we don't want surprise changes to the default behavior (exceptions: fixing bugs). New features should in general be introduced with namelist flags to turn them on, and the default should be the old behavior.
Prefer netCDF output over ASCII (netCDF is standardized, more robust, better tools available, easier for others to process).

MPI indexing, itot, imax
index ranges for the 3D fields are (2:i1, 2:j1, 1:kmax) for historical reasons. i1 = imax+1 and j1 = jmax+1.
ghost cell indexing
time variables, float and integer ms
the top level file calls module procedures, each procedure keeps track of when it should run, tnext
warm starts should be bitwise exact