Thank you very much, David.
I understand that when I know exactly what I want to do, writing a
procedure is a better idea. However, in my case, I was trying to use
batch files to save some keystrokes with plotting.
I was trying to make contour plots with different 2D arrays. These 2D
arrays can all be generated by one single function "make2Darr", which
takes the argument "q", where q is a real number from 0 to 1. I was
trying to make contour plots with different qs and see what's going to
happen.
The following is what I want to do when I try q=0, 0.5 and 0.8:
xaxis=5.0+0.2*findgen(200)
yaxis=3.0+0.1*findgen(200)
z00=make2Darr(0)
contour, z0, xaxis, yaxis, levels=[0], overplot=0
z05=make2Darr(0.5)
contour, z05, xaxis, yaxis, levels=[0], overplot=1
z08=make2Darr(0.8)
contour, z08, xaxis, yaxis, levels=[0], overplot=1
(This is a simplified version of what I was doing. I was having quite
a few more contour keywords set)
I don't want to use a procedure because I do want to keep z00, z05 and
z08 after I finished plotting. They contain useful information and I
might want to shade_surf them or print them.
My own way of doing this task so far is:
<setup.pro>
.compile make2Darr.pro
xaxis=5.0+0.2*findgen(200)
yaxis=3.0+0.1*findgen(200)
<qContour.pro>
zq=make2Darr(q)
contour, zq, xaxis, yaxis, levels=[0], overplot=overplot
IDL>@setup
IDL>q=0
IDL>overplot=0
IDL>@qContour
IDL>z00=zq
IDL>q=0.5
IDL>overplot=1
IDL>@qContour
IDL>z05=zq
...
...
I wonder if there a better way to accomplish this task? In the ideal
situation, I wish I could keyin something like:
"@qContour, 0.5, 1" to accomplish the task done by:
IDL>overplot=1
IDL>@qContour
IDL>z05=zq
Sincerely,
Gene
On Oct 3, 6:40 am, David Fanning <n...@dfanning.com> wrote:
> mystea writes:
>> As far as I can tell, a script:
>> 1. Can't accept any arguments and can't take any extended loops.
>> 2. It can recognize any variable that exists in the current session
>> because it behaves just like a a list of commands in sequence.
>
>> On the other hand, a procedure:
>> 1. Can accept arguments, but can't recognize any variables which exist
>> in current IDL session.
>
> What you are calling a "script", most people call a
> "batch file". This is a way to execute a series of
> commands "as if" you were typing them at the IDL
> command line. Since this is just about the most limited
> way of using IDL, batch files are typically used infrequently.
>
> More often people will put the same commands into
> a file and add an END statement at the end of the file.
> This file is now a "main-level program". It must be
> compiled before it can be executed. Normally the
> compile and execute is done with the .RUN executive
> command. The big advantage of main-level programs over
> batch files, is that you can include extended loops, etc.
> in a main-level program without all the shenanigans
> required to get a loop to work on the IDL command line.
>
> As you become more sophisticated in your programming, you
> will eventually realize that having all your variables
> in one big pot is probably not such a great idea. (Especially
> if you tend to name all your variables "a" to avoid a lot
> of typing.) At that point, you might be interested in writing
> procedures and functions (just another term for "IDL commands")
> that do particular things for you, while at the same time,
> keeping their internal variables from contaminating your
> main-level working space.
>
> IDL uses a "pass by reference" method of getting variables
> into and out of commands, so it is easy to write procedures
> and functions that change main-level variables, if that is
> your purpose. You do, in fact, have to pass the variables into
> the procedure or function via arguments or keywords, however,
> since all the "action" occurs on a level separate from the
> main level. (There are ways to access main-level variables
> from within procedures and functions that don't involve passing
> the variables, but this is rarely done, and only by experienced
> programmers who REALLY know what they are doing and why they are
> doing it.)
>
>> However, I often run into the situation that I need a code which can
>> recognize variables in current session *as well as* taking arguments.
>> Is it possible to write such a code?
>
> This is called "having your cake and eating it, too". It is
> as easy to do in IDL as it is in life. :-)
>
> And, anyway, what could your possibly pass to a batch file
> that the batch file didn't already know about? The only thing
> you can pass are things that exist at the main IDL level, and
> the batch file already has access to all of that.
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
