From bug-request at octave dot org Thu May 26 07:06:19 2005
Subject: Re: matrix determinant calculation
From: Driss Ghaddab <driss dot ghaddab at free dot fr>
To: Hui Zhang <huizhang at ece dot sunysb dot edu>
CC: bug-octave at bevo dot che dot wisc dot edu
Date: Thu, 26 May 2005 14:05:45 +0200

Hui Zhang a écrit :
> hi, i am not sure the following problem is already reported or not.
> It happens both version 2.1.50 (sparc-sun-solaris2.8) and
> version 2.1.57 (i686-pc-linux-gnu).
> 
> octave:1> a=[1,2,3;4,5,6;7,8,9]
> a =
> 
>   1  2  3
>   4  5  6
>   7  8  9
> 
> octave:2> det(a)
> ans =  6.6613e-16   

The answer is correct relative to machine precision. It is equal to 
3*eps. (At least on IEEE 64 bit floating point eps = 2.2204e-16, see 
'help eps').

Cheers.



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