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Re: funny behavior of the sparse


From: David Bateman
Subject: Re: funny behavior of the sparse
Date: Wed, 22 Nov 2006 12:40:06 +0100
User-agent: Thunderbird 1.5.0.7 (X11/20060921)

Yes this is strange, particularly as

spinv(A')'

given a correct result, and internally this is pretty much what is down
with this case... I'll take a look, but can say when I'll get back with
an answer..

D.


Gorazd Brumen wrote:
> Hi,
>
> A = sparse ([1:10, 10], [1:10,5], [1:10 1], 10,10)
> A =
>
> Compressed Column Sparse (rows = 10, cols = 10, nnz = 11)
>
>   (1, 1) ->  1
>   (2, 2) ->  2
>   (3, 3) ->  3
>   (4, 4) ->  4
>   (5, 5) ->  5
>   (10, 5) ->  1
>   (6, 6) ->  6
>   (7, 7) ->  7
>   (8, 8) ->  8
>   (9, 9) ->  9
>   (10, 10) ->  10
>
> octave:5> spinv (A)
> error: division by zero
> warning: spinverse: matrix singular to machine precision, rcond = 0
>
>
> This does not make much sense?
> Tested on Octave 2.9.9 and 2.9.7
>
> Regards,
> Gorazd
>
>
>
>
>   


-- 
David Bateman                                address@hidden
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