From bug-octave-request at che dot utexas dot edu  Sat May 21 20:37:51 1994
Subject: diag([])
From: Ken Neighbors <wkn at leland dot Stanford dot EDU>
To: bug-octave at che dot utexas dot edu (Octave Bug)
Date: Sat, 21 May 1994 18:37:48 -0700 (PDT)

	I'm running Octave 1.0 under
	Linux 0.99.15 #1 Thu Feb 3 19:55:32 CST 1994
	from Slackware 1.1.2 on my 486DX33.

(In my ongoing quest to get the MATLAB controls toolbox to run under
Octave)

Note: I have not changed the default value of
propagate_empty_matrices='true'.

(1) "diag([])" should return [], but it generates an error.

(2) "diag([],-1)" returns [], which is compatible with MATLAB, but it
prints a warning message and it would be nice to be able to turn off
this message so I don't see it all the time.  Maybe if
"empty_list_elements_ok" is TRUE, then diag shouldn't print the
message.

Ken Neighbors
wkn at leland dot stanford dot edu

P.S.  I successfully compiled Octave on my Linux box, and so now I
can actually use all those patches you've been sending.  Thanks.

My octaverc is:
*************** beginning of octaverc *****************
# octave's system startup file

# set load path
LOADPATH=['.:/usr/local/lib/octave/hacks:/usr/local/lib/octave/1.0' ...
        ':/usr/local/lib/matlab/hacks' ...
        ':/usr/local/lib/matlab/controls:/usr/local/lib/matlab/matlab'];

# make octave matlab compatible:
do_fortran_indexing = 'true';
treat_neg_dim_as_zero = 'true';
empty_list_elements_ok = 'true';
*************** end of octaverc *****************

*************** beginning of log *****************
Octave, version 1.0.  Copyright (C) 1992, 1993, 1994 John W. Eaton.
This is free software with ABSOLUTELY NO WARRANTY.
For details, type `warranty'.

octave:1> propagate_empty_matrices 
propagate_empty_matrices = true
octave:2> a = diag([])
diag: requested diagonal out of range
octave:3> a
error: `a' undefined near line 3 column 1
error: evaluating expression near line 3, column 1
octave:4> a = diag([],-1)
diag: requested diagonal out of range
a = [](0x1)
octave:5> 
*************** end of log *****************