Re: [petsc-users] including petsc Mat and Vec in a user-defined structure in FORTRAN

[Lailai Zhu]

thanks, Barray,

indeed this is due to this naive mistake. Thanks again.

best,
lailai

On 04/13/2017 10:34 PM, Barry Smith wrote:

   VecCreate() does not take a size argument (perhaps you mean VecCreateSeq()?) 
hence when you try to get the size it is confused.

    Barry

On Apr 13, 2017, at 8:29 PM, Lailai Zhu <lailaizh...@gmail.com> wrote:

Dear petsc developers and users,

I am currently using fortran version of petsc 3.7.*.
I tried to define Mat or Vec variables in a user-defined structure like below,

module myMOD
    type, public :: myStr
       Mat A
       Vec x,b
    end type myStr

interface myStr !! user-defined constructor
   module procedure new_Str
end interface myStr

contains
    function new_Str()
         type(myStr) :: new_Str
         call  VecCreate(petsc_comm_self,10,new_str%x,ierr)
         call  vecgetsize(new_str%x, size, ierr)
    end function new_Str

end module myMOD


then i define an instance of myStr in another file like below

type(myStr),save :: mystr1
mystr1 = myStr()

It compiles and the veccreate executes without problem, however error occurs on 
the vecgetsize part,
telling me

[0]PETSC ERROR: --------------------- Error Message 
--------------------------------------------------------------
[0]PETSC ERROR: Null argument, when expecting valid pointer
[0]PETSC ERROR: Null Object: Parameter # 1
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for 
trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.7.5, Jan, 01, 2017
[0]PETSC ERROR: ./nek5000 on a pet3.7.5-mpich-intel named quququ by user Thu 
Apr 13 21:11:05 2017
[0]PETSC ERROR: Configure options --with-c++-support --with-shared-libraries=1 
--known-mpi-shared-libraries=1 --with-batch=0 --with-mpi=1 --with-debugging=1 
-download-fblaslapack=1 --download-blacs=1 --download-scalapack=1 
--download-plapack=1 --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpifort 
--download-dscpack=1
[0]PETSC ERROR: #1 VecGetSize() line 667 in 
/home/user/petsc/3.7.5/mpich_intel/src/vec/vec/interface/vector.c

It seems to me that the petsc vector x belong to the derived type variable is 
recognized in the veccreate subroutine, but
not known by the vecgetsize one. Is there way to work this around? or perhaps 
one cannot use petsc objects in such ways?
Thanks in advance,

best,
lailai