Choices to make now

You need to decide whether to modify the Fortran LIBPACKs. If you modify the Fortran LIBPACKs, you make a trade-off between use of storage and faster performance of application programs. See Table 1.

Table 1. Making the trade-off: Performance time versus storage use
Type of Fortran LIBPACK	Performance time	Storage use
Partially loaded	Slower because more routines are loaded individually	Less virtual and shared storage used
Fully loaded	Faster because no routines loaded individually	More virtual and shared storage used

You can use the information in the following sections and the tables in Language Environment Fortran component modules to decide which modules to include in your Fortran LIBPACKs.

Language Environment provides four Fortran LIBPACKs, which you can customize either during or following the installation of Language Environment.

AFHPRNAG
AFHPRNBG
AFH5RENA
AFH5RENB

After installation, each LIBPACK contains a default set of routines. You can remove many of the routines if their functions aren't used frequently at your site, or you can add others that you do use frequently.

Some examples

You can add or remove routines from the Fortran LIBPACKs to reflect the requirements of your location. For example, to include only the group of general routines that your location uses most often, eliminate unnecessary routines from the Fortran LIBPACK.

If you plan to put your Fortran LIBPACK into shared storage and your shared storage space is limited, consider reducing the size of your Fortran LIBPACKs. All modules eligible to be in the Fortran LIBPACKs are reentrant and are therefore eligible to be stored in the shared storage.