Re: User Defined Sources

[Kevin Thomas <kjt@sgi.com>]

Michael,

I think you have the proper input file format.
Judging from the error messages you are seeing, it is likely
that LC cannot find the user defined source input file at all.

LC is not very flexible about these input files.  If you specify
a file name with no directory path, it only looks in the current
directory at the time LC is executed.  In particular, it won't
look into the directory where the model file is stored (if it is
not in the current directory), and it won't remember the current
directory that was relevant when the user-defined source was created.

For example, if I'm in directory /usr/kjt and create a model
file m1.lcx that references a user-defined source input file
called src.xy, then the LC simulation must be run in that same
directory.

If I change to directory /tmp/kjt, then run LC using the original model
file (i.e., I execute the command "lc /usr/kjt/m1.lcx"), it will
fail because LC will only look for src.xy file in /tmp/kjt.

Likewise, if I copy /usr/kjt/m1.lcx to /tmp/kjt/m1.lcx, then
start LC from directory /tmp/kjt, the simulation will also fail.

If I copy both m1.lcx and src.xy into /tmp/kjt, then start LC
after moving to directory /tmp/kjt, then the simulation should
run as expected.  The same sort of copying would be required to
run the simulation on an alternate computer (e.g., a server).

Another way to get around this kind of problem is to specify a full
path name for the user-defined source input file (in this case
"/usr/kjt/src.xy").

A nice enhancement to LC would be for it to also check the directory
from which the model file was read, and possibly the directory
that was the current directory when the model file was created.

It would also be possible for LC to "read in" user-defined source
files when the source is defined, then incorporate the values into
the LC model file itself.  This kind of change would also have three
side effects: later changes to the input file would not change a
simulation run, the model file size would grow, and of course you'd
never have to worry about forgetting to copy user-defined source
input files before running a simulation.

-- 
Kevin Thomas    kjt@cray.com   tel 1-651-683-3624
http://home.cray.com/~kjt/      or 1-800-284-2729 x33624

Saville Michael A 1Lt AFIT/ENAD wrote:
> 
> I'm using plane waves and I have a User defined signal.
> I get the following error message:
> 
> LC: Error
> 
> Input file is not readable
> 
> LC: Wizard's Warning
> 
> Unable to access the input file for the user defined surce.
> 
> I used the following format
> 
> <name>
> Time (sec)
> Electric Field (V/m)
> <#points>
>   < X X >
> 
> Is this the correct format?
> What is the default directory for LC to search for the input file?
> 
> Michael