Re: can't perform indexing operations for <unknown type> type

[Miquel Cabanas]

hello,

On Tue, May 24, 2005 at 04:09:43AM -0700, Kocsis Attila wrote:
> 
> I've experienced a wierd thing recently (at least
> wierd for me...:). So, if I put my code into
> /usr/share/octave/2.1.69/m/own_library, and run it
> from there. Then no error message appeared... I
> thought I could run it from whatever place (eg. my
> home directory), there shouldn't be difference...Ain't
> I right?

the only difference arises from the fact the octave doesn't
search elsewhere, hence, you have to instruct it where to
find your code. Indeed, this holds true for all kind of
computer programs and scripts.

Check the value of DEFAULT_LOADPATH and LOADPATH in a fresh
run,

        octave:1> DEFAULT_LOADPATH
        DEFAULT_LOADPATH = .:/usr/lib/octave  ...

        octave:2> LOADPATH
        LOADPATH = :

> Then where it is advisabe to keep the code and run?

elsewhere as long as you tell octave where to find it. See below,
read the on-line help for `path' and also the manual chapter about
"Getting Started" for details on the several ways to set the M-files
path in octave: command line options, environment variable, general
and user .octaverc files, etc.

> Where is the good place for written data to be kept? I
> guess the closer it is to the beggining of the hard
> disk the faster performance I get...

unless you are really pushing your hardware to the limits you
shouldn't care where your data lives.

> Isn't there a library for data files in octave such as
> there is the /usr/share/octave/2.1.69/m/ for .m files
> (at least for those ones which are not supposed to change...)?

not really sure what you mean by a "library for data files",
you can place your data files wherever it pleases you, and
then tell the `load' command where to find them, or change
into the data directory (`cd ~/data') before loading your
data files.

The standard M-files are part of Octave and are kept in a
common directory grouped in subdirectories.

Your M-files should better be kept in its own directory, e.g.
`/home/<username>/octave/m' that can be added to the search
path with the command,

   > path("~/Octave//", "~/Matlab//", ":";
   > LOADPATH
   LOADPATH = ~/Octave//:~/Matlab//::

note the double forward slash at the end, it tells Octave to search
in all directories under the given directory. Also, note the trailing
colon, it is a short notation for the DEFAULT_LOADPATH variable and
ensures you can continue using all M-files available under the
directories defined in DEFAULT_LOADPATH.

Last, you can save this commands in `.octaverc' at your home
directory so that they are executed everytime you run octave.

Hope this helps,

Miquel


-- 
Miquel E Cabanas ------------------------------------------------------
SeRMN, Universitat Autonoma de Barcelona (address@hidden)
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