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From: Sebastiaan on 2 Nov 2009 04:00
I am glad to be of some help :)

This bug reminds me of something that happend in 2008a. I think it is this bug as well, but it depended on the runtime of the Matlab session.

My work involves mathematical optimization, in which linear systems are solved hundreds of times for 1 problem. The problem was that in a long batch (~1 day) for solving many problems, Matlab crashed somewhere. However, if I restarted that single problem, Matlab did not crash.

So the bug was reproducable for the long run, on different systems (and maybe I have even tried 2007b). However, the matrix which made Matlab crash, did not crash a fresh session.

I fixed it by checking if the reciprocal condition is sufficient prior to solving the system.

Sebastiaan


"Bobby Cheng" <bcheng(a)mathworks.com> wrote in message <hcf8jm$9u5$1(a)fred.mathworks.com>...
> I have not done this myself as I can change this from the inside. :)
>
> But I think you can track the report update and comment of the content.
> Again, I have not tried any on this.
>
> I can assure you that it is the same issue in the bug report. I am
> investigating the issue and have added your matrix into our tests. So thank
> you for the test case.
>
> ---Bob.
>
From: Greg Heath on 2 Nov 2009 07:15
On Nov 2, 5:00 am, "Sebastiaan "
<s.breedv...(a)erasmusmc.REMOVE.BOO.BOO.nl> wrote:
> I am glad to be of some help :)
>
> This bug reminds me of something that happend in 2008a. I think it is this bug as well, but it depended on the runtime of the Matlab session.
>
> My work involves mathematical optimization, in which linear systems are solved hundreds of times for 1 problem. The problem was that in a long batch (~1 day) for solving many problems, Matlab crashed somewhere. However, if I restarted that single problem, Matlab did not crash.
>
> So the bug was reproducable for the long run, on different systems (and maybe I have even tried 2007b). However, the matrix which made Matlab crash, did not crash a fresh session.
>
> I fixed it by checking if the reciprocal condition is sufficient prior to solving the system.
>
> Sebastiaan
>
>
>
> "Bobby Cheng" <bch...(a)mathworks.com> wrote in message <hcf8jm$9u...(a)fred.mathworks.com>...
> > I have not done this myself as I can change this from the inside. :)
>
> > But I think you can track the report update and comment of the content.
> > Again, I have not tried any on this.
>
> > I can assure you that it is the same issue in the bug report. I am
> > investigating the issue and have added your matrix into our tests. So thank
> > you for the test case.
>
> > ---Bob

Why not try rcond, backslash and pinv ?

Greg
From: Sebastiaan on 3 Nov 2009 04:40
Greg Heath <heath(a)alumni.brown.edu> wrote in message <4ca2c11d-c63e-40b8-a04f-58330c624c65(a)h2g2000vbd.googlegroups.com>...
> On Nov 2, 5:00?am, "Sebastiaan "
> <s.breedv...(a)erasmusmc.REMOVE.BOO.BOO.nl> wrote:
> > I am glad to be of some help :)
> >
> > This bug reminds me of something that happend in 2008a. I think it is this bug as well, but it depended on the runtime of the Matlab session.
> >
> > My work involves mathematical optimization, in which linear systems are solved hundreds of times for 1 problem. The problem was that in a long batch (~1 day) for solving many problems, Matlab crashed somewhere. However, if I restarted that single problem, Matlab did not crash.
> >
> > So the bug was reproducable for the long run, on different systems (and maybe I have even tried 2007b). However, the matrix which made Matlab crash, did not crash a fresh session.
> >
> > I fixed it by checking if the reciprocal condition is sufficient prior to solving the system.
> >
> > Sebastiaan
> >
> >
> >
> > "Bobby Cheng" <bch...(a)mathworks.com> wrote in message <hcf8jm$9u...(a)fred.mathworks.com>...
> > > I have not done this myself as I can change this from the inside. :)
> >
> > > But I think you can track the report update and comment of the content.
> > > Again, I have not tried any on this.
> >
> > > I can assure you that it is the same issue in the bug report. I am
> > > investigating the issue and have added your matrix into our tests. So thank
> > > you for the test case.
> >
> > > ---Bob
>
> Why not try rcond, backslash and pinv ?
>
> Greg

Interesting suggestion, I was unaware of the pseudoinverse method. I will have a look at it.

Thank you!
Sebastiaan
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