When you modify data, it is usually best to use a Stored-input file for MODHAR rather than running MODHAR interactively. Then you can repeat
the task (modifying it if necessary) at a later date. The Stored-input file can form part of the documentation of the changes you have carried
out.
Stored-input files for MODHAR are often very long since each modification requires several lines on the Stored-input file. The GEMPACK options
SIF Store inputs on a file
ASI Add to incomplete Stored-input file
can be very useful in building a Stored-input file for MODHAR (or any other GEMPACK program).
Start building a Stored-input file using option SIF. When the job crashes, or when you want to add other modifications, use option ASI (starting
from the file first made with SIF). You can keep using ASI to add to the Stored-input file until it is complete.
It is often difficult to anticipate the questions MODHAR will ask. However, the questions for similar modifications follow the same pattern.
Thus it is often possible to experiment to find the sequence of questions and responses for a prticular type of modification. Then you can copy
this section of the Stored-input file to make other similar modifications. This copying and pasting together with use of option ASI (see 2. above)
make it relatively easy to build Stored-input files for even the most complicated modifications.
Always keep the Stored-input file you used to make a modification.
This file allows you to repeat the task at a later statge. [For example, you might need to make similar changes when you get next year's data
set.]
It also serves as partial documentation of the changes you made.
You can add to this file later if you need to make other changes to the data.