From octave-maintainers-request at bevo dot che dot wisc dot edu Wed Nov 20 21:12:18 2002
Subject: Patching Octave-MPI
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: JD Cole <jdcole at san dot rr dot com>
Cc: octave-maintainers at bevo dot che dot wisc dot edu
Date: Wed, 20 Nov 2002 21:12:07 -0600

On 20-Nov-2002, JD Cole <jdcole at san dot rr dot com> wrote:

|    In the process of patching Andy's MPI support into octave, I have 
| come across the following dilemma: Should I add additional make targets 
| to config files such as Makeconf.in, like this:
| + mpi%.o : mpi%.cc
| +     $(CXX) -c $(CPPFLAGS) $(MPI_DEFS) $(MPI_CPPFLAGS) $(ALL_CXXFLAGS) 
| $< -o $ at 
| 
| %.o : %.cc
|     $(CXX) -c $(CPPFLAGS) $(ALL_CXXFLAGS) $< -o $ at 
| 
| or
| 
| keep with the original:
| 
| %.o : %.cc
|     $(CXX) -c $(CPPFLAGS) $(ALL_CXXFLAGS) $< -o $ at 
| 
| and add MPI_CPPFLAGS to ALL_CXXFLAGS somewhere inbetween configure.in 
| and Makeconf.in (I'm wondering if appending XTRA_CXXFLAGS would be 
| appropriate for this?)

What are these MPI_* variables defined to be?  Are special things
needed because of the way the MPI headers and libraries are installed
on your system, or is it something that is always needed?

| I am partial to the latter solution because it reduces the amount of 
| code duplication in the makefiles. As far as I could see adding MPI 
| includes to the global includes with which octave is compiled shouldn't 
| effect the end result. The situation may be slightly different if I were 
| to add the MPI_LDFLAGS to ALL_LDFLAGS.

What would go in MPI_LDFLAGS?

| Any thoughts?

I've been assuming that we would add a configure option to enable
MPI.  That would add whatever is necessary to the normal INCFLAGS,
etc.

jwe