A Sample IDL Plot, With Colors
This example will illustrate graphing a simple function from the IDL
command line. More complicated graphs are better done from a program
file, so that changes can be made without typing commands over.
ssh to Hodge
On the P&andA system, IDL must be run from hodge. You are probably
logged onto quark. So, you must ssh onto hodge, and then set the
environmental variable DISPLAY to point to your computer. Here is an
example, with more details available:
stars:drodman% rlogin hodge You are Dennis Rodman
(give your password)
hodge:drodman% setenv DISPLAY th12313.sfsu.edu:0.0
Note the capital letters for DISPLAY  Unix is casesensitive. The name
given is that of one of the computers in TH 123.
Graphs of Straight Lines
Open IDL and try a simple straightline graph.
hodge:drodman% idl
IDL> plot,indgen(100)
Resize your windows for convenience.
Now create an array with the values (0.,1., . . . 999.), print it out,
and plot it:
IDL> t = findgen(1000)
IDL> print,t
IDL> plot,t
Graph of a Train of DeBroglie Wave Packets
Now try the following sequence, which plots a sort of
deBrogliewave packet, and then fancies it up in various ways.
The semicolon and following text are comments, and do not need
to be typed in. Note that you do not need to retype
the command each time. IDL stores a buffer of previous
commands, accessible using the uparrow. It is much more
efficient when repeating a command to find it in the command
buffer, and when making a change, to call up the previous
command and change it.
IDL> plot,sin(t/7)+sin(t/8)
IDL> plot,sin(t/7)+sin(t/8),title='deBroglie Waves'
IDL> plot,sin(t/7)+sin(t/8),title='deBroglie Waves',xtitle='time (ns)'
IDL> loadct,32
% Compiled module: LOADCT.
% Compiled module: FILEPATH.
% LOADCT: Loading table Plasma
IDL> loadct,33
% LOADCT: Loading table BlueRed
IDL>
Overplotting
Try this:
IDL> plot,sin(t/5)
IDl> oplot,sin(t/5)*exp(t/200)
