Loving ISIS - Confessions of a Former XSPEC User

Five Basics:

The ISIS manual gives an overview of its commands and syntax, as well as an introduction to S-lang syntax in general. See the ISIS manual for how to start up ISIS and how to load analysis scripts. There are five useful things to remember, however, that will help you during an analysis session:

• The who; command will give you a list of the variables that you have defined on the command line during the session (but won't list the global variables loaded from scripts).
• The .apropos command (which doesn't require an ending semi-colon!) will give you a list of commands (including globally defined functions imported from scripts) that contain a given substring.
• The .help command (which also doesn't require the semi-colon) will give you a help file for most ISIS intrinsic commands.
• Many commands (including most of the functions defined by my .isisrc file) will give you a usage message if they are invoked without any arguments.
• Any command name that you don't like you can alias to a name that you do like. Commonly used aliases and custom defined S-lang functions can be stored in your home directory in an .isisrc file, which will be loaded everytime you start ISIS. (Invoking ISIS as: unix%> isis -n will run ISIS without loading your .isisrc)

Welcome to ISIS Version 1.2.9
Copyright (C) 1998-2005 Massachusetts Institute of Technology

isis> a = [0:10]; b = 3.5; c = "pizza";
isis> who;
a: Integer_Type[11]
b: 3.5
c: pizza
isis> .apropos load
Found 27 matches in namespace Global:
_load_xspec_local_models   add_to_isis_load_path      append_to_isis_load_path
autoload                   get_isis_load_path         get_slang_load_path
load_all                   load_alt_ioniz             load_arf
load_conf                  load_data                  load_dataset
load_fit_method            load_fit_statistic         load_hexte
load_kernel                load_model                 load_par
load_pca                   load_radio                 load_rmf
load_xspec_fun             load_xspec_local_models    mt_load_model
prepend_to_isis_load_path  set_isis_load_path         set_slang_load_path

isis> .help load_arf
Searched: /usr/local/isis/doc/local_help.txt
Searched: /usr/local/isis/doc/cfitsio.hlp
load_arf

 SYNOPSIS
    Load an effective area (ARF) file

 USAGE
    status = load_arf ("filename")

 DESCRIPTION
    This function loads either a FITS Type I or Type II ARF file;
    the updated list of currently loaded ARFs is automatically
    displayed. On return, status is equal to the integer index of
    the ARF just loaded ( status > 0); a return value of status =
    -1 is used to indicate failure.  (For Type II ARF input, a
    return value of zero indicates success).


 SEE ALSO
    load_dataset, list_arf, delete_arf, assign_arf, unassign_arf

isis> load_radio;

 radio_id = load_radio(radio_struct);

    Takes the structure output from `read_radio();' and loads
    it up for fitting.  Also ignores all the zero count
    channels.  (Note: Those could come back if any further filters
    are applied.)

isis> alias("load_arf","arf");
isis> alias("fit_fun","model");

We now begin to load the data.