RE: invfreqs broken?

[John W. Eaton]

On  3-Aug-2007, Schirmacher, Rolf wrote:

| 
| Tracing the problem back as indicated gives in invfreq, line 76:
| 
|  if nargin < 8, tr = ''; end
| 
| and in line 84:
| 
|   if tr == 'trace'
| 
| The latter check seems to be the one that breaks. Indeed, doing
| 
| octave.exe> tr = 'a';
| octave.exe> if tr == 'trace'
| > disp('successs')
| > end
| octave.exe> 
| 
| does nothing (as expected) and especially do not give errors, but
| 
| octave.exe> tr = '';
| octave.exe> if tr == 'trace'
| > disp('success')
| > end
| error: mx_el_eq: nonconformant arguments (op1 is 0x0, op2 is 1x5)
| error: evaluating binary operator `==' near line 14, column 7
| error: if: error evaluating conditional expression
| error: evaluating if command near line 14, column 1
| octave.exe> 
| 
| breaks. It looks like == does not handle empty strings correctly. As I am
| not that deep inside octave, perhaps there are some ideas out there?

The == operator requires that the operands have the same size.  To
compare character strings, you should use strcmp, strncmp, etc.

Note that the invfreq* functions are part of an Octave Forge package,
not Octave itself, so this problem should be reported to the
address@hidden mailing list.

jwe