We have found that in very rare cases the alias hidl is not recognised by the user's system. Usually, this is related to the local system's IDL script. A quick-fix is achieved by setting the environment variable IDL_STARTUP to be equal to the HEALPix startup file HEALPix_startup including the directory path to the file. This enables the user to access the HEALPix IDL procedures simply by invoking IDL. For example, in the typical installation documented above for a user running the tcsh shell, the command
setenv IDL_STARTUP /disk1/user1/HEALPix_2.00/src/idl/HEALPix_startupshould be issued (or added to the user's shell profile).
If the user already has an IDL startup file, then this should be merged with HEALPix_startup. This temporary solution does mean that the HEALPix IDL procedures are available in the IDL_PATH at all times, which may lead to conflicts with user-defined procedures. The hidl invocation was intended to circumvent these issues, allowing HEALPix IDL procedures to be available only when desired.
A proper fix requires the user to ask the local system administrator to adjust the local IDL script.
Eric Hivon 2005-08-31