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</o:shapelayout></xml><![endif]--></head><body lang=DA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>I’m confused about the matview command, or rather, it’s output. The following lines of code:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> int rank;<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> MPI_Comm_rank(PETSC_COMM_WORLD,&rank);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> MatView((*FD).ddx,PETSC_VIEWER_STDOUT_WORLD);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> int fr,lr;<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> MatGetOwnershipRange((*FD).ddx,&fr,&lr);<o:p></o:p></span></p><p class=MsoNormal style='text-indent:4.5pt'><span lang=EN-US>printf("process %d has rows %d to %d\n",rank,fr,lr);<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Produce the following output:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>>mpirun -np 4 ./petsclapl <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> Matrix Object: 1 MPI processes<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> type: mpiaij<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> row 0: (0, 5) (1, 5) (12, 0) (13, 0) (108, 0) (109, 0) <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> row 1: (0, -5) (1, 0) (2, 5) (12, 0) (13, 0) (14, 0) (108, 0) (109, 0) (110, 0)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>[snip]<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> process 0 has rows 0 to 30<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> process 1 has rows 30 to 60<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> process 2 has rows 60 to 90<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US> process 3 has rows 90 to 120<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>My question is this: How come the MatView command states 1 MPI processes, while, when I use GetOwnershipRange, the (expected) division into ¼ of the rows at each process is reported? Is the MatView “processes” the process of the viewer? And more importantly, what is the actual position of my matrix – is it on 1 or on 4 processes?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>---<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>yours sincerily<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Frederik Treue<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div></body></html>