Re: [Help-gsl] is gsl_integration_workspace reusable?

[Andrew W. Steiner]

I'm wondering if the problem might be in the extrapolation table qags uses to
approach the singularity? You might try editing initialise_table in qelg.c to
initialize rlist2[0] and res3la[0] to 0.0 and recompiling GSL and then
running...

Take care,
Andrew

On Thu, Dec 1, 2011 at 2:33 PM, Rhys Ulerich <address@hidden> wrote:
> Hi Denes,
>
>> Unfortunately our 'test' code is 400-500 lines. We may be able to reduce it
>> in the coming weeks. Apart from all the bells and whistles, the original
>> code allocated a single workspace and then used that in a loop to compute
>> billions of integrals (calls to gsl_integration_qags()) with stochastic
>> parameters. The results were really strange (and wrong) until we changed the
>> code to allocate a workspace for every single integration.
>
> Any chance your test code is overwriting memory in places where it
> shouldn't?  If it trampled the gsl_integration_workspace I'd expect
> similar behavior which might be resolved by allocating new workspaces
> all the time.  What does valgrind say?  Do you see identical (or
> identically strange) results across different compiler versions or
> optimization levels?
>
> 400-500 lines isn't ideal but it'd be usable if you can reproduce the
> issue with O(2) iterations instead of billions.
>
> - Rhys
>
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