dolfin team mailing list archive

["Matthew Knepley" <knepley@xxxxxxxxx>]

On Fri, Jun 20, 2008 at 3:41 PM, Anders Logg <logg@xxxxxxxxx> wrote:
> On Fri, Jun 20, 2008 at 06:08:04AM -0500, Matthew Knepley wrote:
>> On Fri, Jun 20, 2008 at 3:13 AM, Ilmar Wilbers <ilmarw@xxxxxxxxx> wrote:
>> > This issue keeps coming up again and again.
>> >
>> > The question is whether to use PETSC_TS_LIB or not. I think the last
>> > email on this subject is this one:
>> > http://article.gmane.org/gmane.comp.mathematics.fenics.dolfin/2124
>>
>> 1) PETSc ONLY modifies a library to fix bugs which the maintainers refuse to
>>     fix,so you really should not be using an unmodified version.
>>
>> 2) I think we are fairly fast on updating to the latest version, and
>> we always do
>>     it if someone asks.
>>
>>    Matt
>
> Yes, but even so it's not a good idea that DOLFIN must depend on the
> exact versions of libraries that PETSc chooses (however good that
> reason may be).
>
> Say we have the following situation:
>
>  A depends on B and C
>  B depends on C'
>
> where C' is a modified version of C. Then we shouldn't need to require
> that A depends on C'.
>
> To be precise, we may take
>
>  A  = DOLFIN
>  B  = PETSc
>  C  = UMFPACK in Ubuntu
>  C' = UMFPACK modified by PETSc

What modifications other than bug fixes are you talking about?

> DOLFIN should be able to depend on C and not on C'.
>
> This should all work fine as long as PETSc is built with
>
>  --with-shared=1
>
> because then there is a mechanism for resolving the dependencies.
>
> On the other hand, if PETSc is built with static libraries, then there
> is no way to resolve this, other than forcing DOLFIN to use the same
> libraries as PETSc. Right?

Just force PETSc to use the version you want. It will work fine as long as the
package has no outstanding bugs.

   Matt

> --
> Anders
>
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What most experimenters take for granted before they begin their
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