Re: [ublas] Serious bug in mapped_vector_of_mapped_vector [patch]

From: Matthias Troyer (troyer_at_[hidden])
Date: 2006-11-10 10:52:50

On 7 Nov 2006, at 15:19, Gunter Winkler wrote:

> On Thursday 07 September 2006 14:04, Gunter Winkler wrote:
>> On Sunday 23 July 2006 11:13, Matthias Troyer wrote:
>>> There is a serious bug in the mapped_vector_of_mapped_vector spare
>>> matrix type. Rows containing only zero elements are not treated
>>> correctly in prod(). The following code should give a vector that
>>> contains only 1 in the last element. Instead prod() gives a vector
>>> containing 1 in each element. In debug mode this bug is found by the
>>
>> I could reproduce the bug. It is inside the vector_assign logic. The
>> product is correctly computed, but the assignment fails. I will  
>> give more
>> details shortly.
>
> I finally found the bug and (hopefully) fixed it. The patch and  
> sample program
> is attached. Is someone using mapped_vector_of_mapped_vector in a  
> larger
> program? I'd like to know if the changes have any unexpected side  
> affect.

A first test with our full application shows that the problem is  
resolved and no new problems have appeared. We will do more tests as  
we prepare the final release and will let you know if we should  
encounter any unforeseen problem.

I hope that this patch will make it into the 1.34 release

Matthias