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cond(zeros(4))
From: 
John W. Eaton 
Subject: 
cond(zeros(4)) 
Date: 
Fri, 9 Jul 1999 10:35:31 0500 (CDT) 
On 29Jun1999, address@hidden <address@hidden> wrote:
 I type in

 cond(zeros(4))

 and get NaN. I know this is the IEEE analogue of the strict
 mathematical definition, but since I'm using this quantity to
 test how close a matrix is to singular, it would have been nicer
 to get Inf.
OK, I've fixed this in my sources using the following logic:
if (any (any (isinf (a)  isnan (a))))
error ("cond: argument must not contain Inf or NaN values");
else
sigma = svd (a);
sigma_1 = sigma(1);
sigma_n = sigma(length (sigma));
if (sigma_1 == 0  sigma_n == 0)
retval = Inf;
else
retval = sigma_1 / sigma_n;
endif
endif
Does anyone see a problem with that?
BTW, please report bugs to the bugoctave mailing list.
Thanks,
jwe

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