On Fri, Jun 20, 2008 at 04:51:52PM -0500, Matthew Knepley wrote: > On Fri, Jun 20, 2008 at 3:41 PM, Anders Logg <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]> 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?
I don't know what modifications are usually in the PETSc-modified packages, but I don't think it matters. I should be able to build an application against the packages installed system-wide by my package manager (in my case the standard Ubuntu-packages). I should not need to build my applications against /usr/local/lib/petsc/externalpackages/UMFPACKv4.3/linux-gnu-cxx-debug/UMFPACK/Lib/ PETSc can do this, but it should not force applications compiled against PETSc to choose the PETSc-version if there's a system-wide default version available. > > 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 ok. So I guess there are two solutions: 1. Configure PETSc for shared libs. Then PETSc can download its own version. 2. Configure PETSc to use the default version of the external package. -- Anders
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