By default, pyrrtm uses intermediate NetCDF files to communicate with the RRTM binaries. This is a very reliable method, but has an overhead associated with writing the data to disk, calling RRTM, and finally reading the output from disk.
If you installed the Full installation of pyrrtm version of pyrrtm, you have access to a much faster native interface to RRTM, meaning that RRTM is loaded as a shared object by the python interpreter. Practically speaking, this should increase the performance of the longwave code by 5 to 10 times. The shortwave code performance is not so dramatically affected as the code itself takes much longer to run than the overhead. A big disadvantage of the native interface is that errors thrown by RRTM are not handled at all and will often kill the python interpreter. As such, the native interface is always disabled by default but can be activated using use_native().
Activates and deactivates the native binary interface. state is a boolean value that sets the state of the native binary interface.
Indicates whether pyrrtm has been compiled with support for the native interface.