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Ublas : |
From: Manoj Rajagopalan (rmanoj_at_[hidden])
Date: 2006-04-13 15:52:36
I can confirm that this code will crash on singular matrices :-) Can't
ublas be modified to throw an exception or return an error value like
INFO in the original FORTRAN version?
Sohail Somani wrote:
> Warning: I think the wiki says that this code will crash on a singular
> matrix.
>
> Just fyi.
>
>
>>-----Original Message-----
>>From: ublas-bounces_at_[hidden]
>>[mailto:ublas-bounces_at_[hidden]] On Behalf Of Manoj Rajagopalan
>>Sent: Thursday, April 13, 2006 7:06 AM
>>To: ublas mailing list
>>Subject: Re: [ublas] Solving linear equations of the form Ax = b ?
>>
>>you can solve Ax=b using three lines of ublas code:
>>
>>permutation_matrix<> piv;
>>lu_factorize(A, piv);
>>lu_substitute(A, piv, x);
>>
>>Then x will contain the solution and A is overwritten with its LU
>>decomposition. i.e., the original values of A and x are
>>destroyed so the
>>above lines are actually the inplace_solve(A, x) for a dense,
>>generic A.
>>
>>BTW, I've come across this in many places - what does
>>"boilerplate code"
>>mean and why is it called so?
>>
>>cheers!
>>Manoj
>>
>>
>>
>>John Maddock wrote:
>>
>>>I gather from a quick web search that ublas does have LUP
>>
>>decomposition
>>
>>>routines, however a grep of the docs failed to find any
>>
>>mention of the
>>
>>>routine in question, and how they should be used.
>>>
>>>So.... does anyone have the boiler plate code needed to
>>
>>solve for x given
>>
>>>matrix A and vector b ?
>>>
>>>Many thanks,
>>>
>>>John Maddock.
>>>
>>>_______________________________________________
>>>ublas mailing list
>>>ublas_at_[hidden]
>>>http://lists.boost.org/mailman/listinfo.cgi/ublas
>>
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>
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