Re: [Closed REQ 5163]: Question regarding external module

["Tamara Munzner" <munzner>]

>	How do I handle this in the emodule-define... command?

First, you could write emodule-define commands that hardwire the
name of the input and output files, eg
 (emodule-define "my module" "mpm file1 file2")
 (emodule-define "mymod/file3/file4" "mpm file3 file4")
 (emodule-define "mymodv3" "mpm file5 file6")

This is only convenient if you generally use only a small number of
standard configurations. If you'd like to be able to type input
filenames when the module is invoked, you can communicate with your
module via standard error (file descriptor 2). Then you'd invoke it
with
 (emodule-define "my module" "mpm <&2")
and your program would have code like
	fprintf(stderr, "input file 1? ");
	scanf("%s", file1);
	fprintf(stderr, "input file 2? ");
	scanf("%s", file2);

> can I print stuff other than
> what Geomview needs at the standard output, like iteration number, variable 
>values, etc?

Note that you can also you stderr to write out iteration numbers, in
answer to question 2. You'd just say something like
 	fprintf(stderr, "iteration: %d x: %f y: %f", itnum, x, y);


> 2) Can Geomview read data from only the standard output of the external
> module. Can't I read data from the .off and .vect files in which I dump 'em?

Yes, you can tell Geomview to read a .off or .vect file. You can have
your program send Geomview a command like
  	(geometry "newthing" { < file.off })
or even just 
  	(load file.off}

Depending on your needs, you might want to set up the external module
so that's there's an option to just dump its output files directly
into the Geomview display without the intermediate step of saving them
to disk.


>3) Can only executable files be used as external modules? Can I use the .off
>and .vect files as external modules? In other words, is it possible that 
>when I invoke Geomview, I don't have to load these data files, rather they are
>are already there and I have to just click on a particular file to display it?

Well, if there are particular configurations of geometry files that
you commonly use you could make "external module wrappers" to load
them in, for instance
 (emodule-define "config1" "( progn (load file1.off) (load file2.vect) )")
 (emodule-define "config2" "( progn (load file1.off) (load file4.off)
(load file3.off) (load file19.vect) )")

and so on. It wouldn't make much sense to do something like
 (emodule-define "loadfoo" "(load foo.off)")

since it's as easy to click on the line "foo.off" in the file browser
as it is to click on "loadfoo" in the modules browser. (The "progn"
command groups other commands as a single unit, so they all execute
before interactive control resumes. It's a good idea to wrap multiple
commands that should be executed simultaneously in a "progn".)

Also, you can put any command you'd like into a file named .geomview,
which is read at startup time. If you always want to load the same two
pieces of geometry, you could just put commands to load them
automatically in your .geomview file.

>Thanks a lot for your help. Geomview has really been of great help to me.

We're always glad to hear that it's useful!

Hope this helps, let us know if you need more clarification or have
more questions.

Tamara Munzner		The Geometry Center	     ((555) 555-5555
munzner at geom.umn.edu    http://www.geom.umn.edu/people/munzner.html