Differences in SITAR Implementation in ISIS vs. Sherpa

The purpose here is not to make comparisons between ISIS and Sherpa, but rather to highlight the differences between the implementation of the SITAR code in each. As of SITAR version 0.3.0, there is only a single file for the main code, as well as for all driver and example subroutines, that can be used in either ISIS or Sherpa. For use in Sherpa, the codes contain a few extra lines wherein the required ISIS functionality is imported into the Sherpa namespace. (The imported functions are clearly delineated in the headers of the subroutines.)

I will also endeavor to keep the imported functions down to a minimum in both the the main code and the driver scripts, found in the examples. The most substantial differences between ISIS and Sherpa will pertain to plotting functions (for the most part, I am defaulting to PGPLOT routines imported from ISIS), and these will primarily be found in the example subroutines.

Occasionally, additional code, not native to either ISIS or Sherpa, will be required. For example the GSL module from the S-Lang Modules Packages can be used to provide statistical significances of the epoch fold. This will be noted here on these web pages as well as in the headers of the subroutines.

Important Note: Before running the code, it is best if only one of either ISIS or Sherpa, but not both, is set-up. This is to avoid conflicting pathnames, etc., which can lead to such problems as Sherpa being unable to import its proper version of ISIS. There is no problem running the codes serially. E.g., set up Sherpa, run, exit, clear the paths, then run ISIS. Problems potentially will occur if both codes and their respective paths, libraries, etc., are set at the same time.