feature/single precision

[climbfuji]

WORK IN PROGRESS

• Switch working precision to single precision of preprocessor flag -DSINGLE_PRECISION is set

[RobertPincus]

@climbfuji Note the same functionality is already on the develop branch in commit 345aefb.

I like to move things from develop to main and then out to autoconf and ccpp. If this is pressing please let me know and I'll update main.

Note also that this won't work - some calculations will fail if done in single precision. This is something we're working on and can prioritize if you have an immediate need.

[climbfuji]

@climbfuji Note the same functionality is already on the develop branch in commit 345aefb.

I like to move things from develop to main and then out to autoconf and ccpp. If this is pressing please let me know and I'll update main.

Note also that this won't work - some calculations will fail if done in single precision. This is something we're working on and can prioritize if you have an immediate need.

@RobertPincus Absolutely agree. You'll be receiving an email in a second that provides more background.

[Chiil]

Would it be a good idea to add a prefix RTE_RRTMGP_ or something similar to preprocessor flags?

[RobertPincus]

Closed with a4fe30c but note that code compiled as single precision almost certainly won't work.