From help-octave-request at bevo dot che dot wisc dot edu  Sun Nov 28 21:59:29 1999
Subject: Re: Sparse functions for octave
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: A+A Adler <adler at mondenet dot com>
Cc: help-octave at bevo dot che dot wisc dot edu
Date: Sun, 28 Nov 1999 21:59:00 -0600 (CST)

On 27-Nov-1999, A+A Adler <adler at mondenet dot com> wrote:

| On Tue, 16 Nov 1999, John W. Eaton wrote:
| > On 16-Nov-1999, A+A Adler <adler at mondenet dot com> wrote:
| > | Great, thanks. I've now got indexing working on sparse variables.
| 
| I have a few more questions about indexing
| 
| 1. When M(idx,:) is specified, what is the idx_vector set to
|    for the ':' ?

You can use the method

  int is_colon (void) const;

which returns nonzero if the index is `:'.

| 2. What methods does [ M1, M2 ] map to internally?

Hmm.  None really.  This is something that probably needs to be
changed.  The parser handles the details of matrix construction.  When
I wrote it, I didn't fully anticipate the need to handle other types
of objects in these expressions.

| Also, while putting together a test script for the sparse 
| functions I use exist('__OCTAVE_VERSION__') to destinguish
| octave from Matlab. This no longer works in 2.1.19
| 
|    octave-2.1.19:1> __OCTAVE_VERSION__ 
|    __OCTAVE_VERSION__ = 2.1.19
|    octave-2.1.19:2> exist('__OCTAVE_VERSION__')
|    ans = 0
|    
| However,   
|    octave-2.0.14:1> __OCTAVE_VERSION__
|    __OCTAVE_VERSION__ = 2.0.14
|    octave-2.0.14:2> exist('__OCTAVE_VERSION__')
|    ans = 1

This is a bug that should be fixed now, at least in the CVS archive.

jwe



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