TYPICAL STRUCTURE OF AN ASTERIX PROGRAM

The general structure of an ASTERIX program might look like this:

• Announce application name and version

• AST_INIT - Initialises ASTERIX subroutine packages

• USI_ASSOC* - Get locator(s) to input (and maybe also output) file(s)

• Check data (e.g. dimensionality) and map if OK (using BDA_* routines)

          If data not primitive
                  Check for regular axes and map          } Using
                  Map variance                            } BDA_*
                  Map quality (as array of logicals)      } routines
          Endif
  

• Make any additional checks

• Further user input (N.B. Use PRS_GETRANGES for any numerical range specifications)

• USI_ASSOCO - create output file (if not already done above)

• Create components in output file (e.g. BDA_CREBDS) or copy from input file (BDA_COP*)

• Map output data, and maybe variance and quality (using BDA_*)

• Pass pointers to input and output data to main subroutine to perform the computations

• Copy ancillary information from input to output files (e.g. BDA_COPMORE)

• Write any special components, labels etc. to output file

• Make HISTORY entry in output file (using HIST_*)

• AST_CLOSE - shut down ASTERIX subroutine packages