Dear Pierre and Stefano,
                                          Yes - that is it!  I had just stumbled onto that
point as your email arrived thanks to Stefano's guidance, which suggested the problem was that the routine
was receiving an integer when it was expecting something else... then a lightbulb
 finally switched on and I finally remembered that I needed to add the error variable
 as a final argument. I thought it was something silly on my part, and I wasn't mistaken
there at least!
      Many thanks to both of you,
                best wishes,
                             Dan.

From: Pierre Seize <pierre.seize@onera.fr>
Sent: Friday, April 9, 2021 10:14 AM
To: Stefano Zampini <stefano.zampini@gmail.com>; dazza simplythebest <sayosale@hotmail.com>
Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov>
Subject: Re: [petsc-users] Newbie question: Strange failure when calling PetscIntView from slepc application
 

Hello, I think you forgot to pass ierr as the last argument of PetscIntView.

Pierre


On 09/04/21 11:52, Stefano Zampini wrote:
==841883== Invalid write of size 4
==841883==    at 0x503E784: petscintview_ (/data/work/slepc/PETSC/petsc-3.14.5/src/sys/error/ftn-custom/zerrf.c:109)
==841883==    by 0x40262C: all_stab_routines_mp_write_rows_to_petsc_matrix_ (/data/work/rotplane/omega_to_zero/stability/test/tmp10/tmp3/tryme.F:17)
==841883==    by 0x402465: MAIN__ (/data/work/rotplane/omega_to_zero/stability/test/tmp10/tmp3/tryme.F:40)
==841883==    by 0x402221: main (in /data/work/rotplane/omega_to_zero/stability/test/tmp10/tmp3/trashy.exe)
==841883==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==841883== 

This exactly points to the error and suggests you to take a look at /data/work/slepc/PETSC/petsc-3.14.5/src/sys/error/ftn-custom/zerrf.c, line 109
You are trying to write 4 bytes (most probably an int) where is not allowed.

On Apr 9, 2021, at 12:32 PM, dazza simplythebest <sayosale@hotmail.com> wrote:

==841883== Invalid write of size 4
==841883==    at 0x503E784: petscintview_ (/data/work/slepc/PETSC/petsc-3.14.5/src/sys/error/ftn-custom/zerrf.c:109)
==841883==    by 0x40262C: all_stab_routines_mp_write_rows_to_petsc_matrix_ (/data/work/rotplane/omega_to_zero/stability/test/tmp10/tmp3/tryme.F:17)
==841883==    by 0x402465: MAIN__ (/data/work/rotplane/omega_to_zero/stability/test/tmp10/tmp3/tryme.F:40)
==841883==    by 0x402221: main (in /data/work/rotplane/omega_to_zero/stability/test/tmp10/tmp3/trashy.exe)
==841883==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==841883==