[Wien] lapw0_mpi (MPI_Bcast) bug

[Laurence Marks]

There is a bug in some mpi implementations that can lead to a SIGSEV
in lapw0_mpi for large problems. The symptom is a SIGSEV at the
MPI_Bcast call
at about line 1574:
#ifdef Parallel
 if (.not.coul)  allocate(potk(nkk))
 call MPI_Bcast(potk, NKK, MPI_DOUBLE_COMPLEX, 0,MPI_COMM_WORLD , ierr)
#endif

A patch (works) is to not do the MPI_Bcase all at once:

#ifdef Parallel
      if (.not.coul) allocate(potk(nkk))
      ibbuff=32768  ! Could be optimized
      i2=NKK/ibbuff
      it1=1
      do i=1,i2
        call MPI_Bcast(potk(it1), 1024, MPI_DOUBLE_COMPLEX ,
0,MPI_COMM_WORLD , ierr)
        it1=it1+ibbuff
      enddo
      if(it1 .lt. nkk)then
        it2=nkk-it1+1
        call MPI_Bcast(potk(it1), it2, MPI_DOUBLE_COMPLEX ,
0,MPI_COMM_WORLD , ierr)
      endif
      call MPI_BARRIER(MPI_COMM_WORLD,ierr)
#endif


-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
Chair, Commission on Electron Crystallography of IUCR
www.numis.northwestern.edu/
Electron crystallography is the branch of science that uses electron
scattering and imaging to study the structure of matter.