[mpich-discuss] Error while using MPI platform with CPP program
Umesh Shisode
ushisode1 at gmail.com
Thu May 21 06:54:43 CDT 2015
Hello Antoine Rougier,
I did not understand, [You have to change your code if you want to keep
using blocking communication.] you ask me about. Also now the code is
working fine, but it is only for same process and same numbers of rows. For
other cases it is giving me error (segmentation fault). Please check it, I
am attaching here the tar file of compile code. But it is working for only
following commands
>> mpic++ main.cpp -o result
>> mpirun -np 4 result
But for this case input matrix is (4 X 4) only.
If you find any mistake please let me know.
Regards,
Umesh Sharad Shisode,
M.Tech in Modeling and Simulation(2013-15),
Centre for Modeling and Simulation,
University of Pune.
On Wed, May 20, 2015 at 11:29 PM, Antoine Rougier <rougier at par.tuwien.ac.at>
wrote:
> First, as far as I understand, the broadcast should not be between
> blocking send on a process and blocking recv on the others. You have to
> change your code if you want to keep using blocking communication.
>
> Then, by running (with the previous modifications), I have got:
> Fatal error in MPI_Recv: Invalid buffer pointer, error stack:
> MPI_Recv(187): MPI_Recv(buf=(nil), count=8, MPI_DOUBLE, src=0, tag=3,
> MPI_COMM_WORLD, status=0x7fffbc4e02d0) failed
> MPI_Recv(126): Null buffer pointer
>
> It is probably an issue on your side, such as bad index.
>
> Antoine Rougier
>
> On 05/20/2015 05:17 PM, Umesh Shisode wrote:
> > Hello Antoine Rougier,
> >
> > Thanks for your reply. Now I have code which can broadcast vector as well
> > as Matrix object (Attached here). But it is giving error when I tried to
> > send and receive part of matrix object it is giving me error. Thanks
> again
> > for your time. Please help me out. As it is not giving me correct
> answer. I
> > am waiting for your reply.
> > Sorry for your inconvenience.
> >
> > I have attached here new code. It compiles when I want to broadcast. But
> > giving error for send and receive. I also attached error in png file.
> >
> > Regards,
> >
> > Umesh Sharad Shisode,
> > M.Tech in Modeling and Simulation(2013-15),
> > Centre for Modeling and Simulation,
> > University of Pune.
> >
> > On Wed, May 20, 2015 at 4:07 PM, Antoine Rougier <
> rougier at par.tuwien.ac.at>
> > wrote:
> >
> >> Hello,
> >>
> >> I think your issue comes from b.vect=NULL (according to the used
> >> constructor) which is not a checked value in T Vector<T>::get(int i). By
> >> the way Ncol is no initialized before using it in MPI_Bcast.
> >>
> >> best regards,
> >>
> >> Antoine Rougier
> >>
> >>
> >> On 05/20/2015 11:55 AM, Umesh Shisode wrote:
> >>> Hello Junchao,
> >>>
> >>> I initialize vector b, but even then it is not working for
> broadcasting.
> >> It
> >>> gives same error. As the vector class is user defined and also I use
> >>> dynamic memory allocation. This may be the reason for failing. If you
> >> know
> >>> about it then please tell.
> >>> I am here attaching the zip file which contains only the vector class
> and
> >>> main file as well as error I am facing. Please have a look at it.
> Thanks
> >>> for your time. I am waiting for your reply.
> >>>
> >>>
> >>> Regards,
> >>>
> >>> Umesh Sharad Shisode,
> >>> M.Tech in Modeling and Simulation(2013-15),
> >>> Centre for Modeling and Simulation,
> >>> University of Pune.
> >>>
> >>> On Tue, May 19, 2015 at 10:57 PM, Junchao Zhang <jczhang at mcs.anl.gov>
> >> wrote:
> >>>
> >>>> Your code "MPI_Bcast(&b(0), b.get_row(), MPI_DOUBLE, 1,
> MPI_COMM_WORLD)"
> >>>> is OK. You can find manual of MPI_Bcast at
> >>>> http://mpi.deino.net/mpi_functions/MPI_Bcast.html
> >>>> Don't forget to initialize the vector b, in other words, allocate
> memory
> >>>> for it, on ALL ranks.
> >>>>
> >>>>
> >>>> --Junchao Zhang
> >>>>
> >>>> On Tue, May 19, 2015 at 9:27 AM, Umesh Shisode <ushisode1 at gmail.com>
> >>>> wrote:
> >>>>
> >>>>> Hi Junchao,
> >>>>>
> >>>>> I sort out the problem for MPI_Send() and MPI_Recv(), as I requested
> in
> >>>>> last mail. Now I have one more difficulty which is how can I
> broadcast
> >>>>> class object using MPI_Bcast() function. In my case, class is Vector
> >> (you
> >>>>> can check it at vect_fun.h header file). I want to broadcast it to
> all
> >>>>> processes. I have used dynamic memory allocation in the code. Please
> >> help
> >>>>> me to solved the issue. I am waiting for your reply. Thanks.
> >>>>>
> >>>>>
> >>>>> Regards,
> >>>>>
> >>>>> Umesh Sharad Shisode,
> >>>>> M.Tech in Modeling and Simulation(2013-15),
> >>>>> Centre for Modeling and Simulation,
> >>>>> University of Pune.
> >>>>>
> >>>>> On Tue, May 19, 2015 at 7:51 AM, Umesh Shisode <ushisode1 at gmail.com>
> >>>>> wrote:
> >>>>>
> >>>>>> Sorry Junchao,
> >>>>>>
> >>>>>> Thanks for your reply. But my problem is with MPICH only. My
> question
> >> is
> >>>>>> how to send part of class object (in my case matrix object) from one
> >>>>>> process to another process using MPI_Send and receive using MPI_Recv
> >>>>>> functions. I tried a lot of way but couldn't do it. I hope you will
> >> help
> >>>>>> me. Thanks in advance. I have write a function to get the pointer
> >> address
> >>>>>> for first parameter of MPI_Send() function. Waiting for your reply.
> >>>>>>
> >>>>>> Regards,
> >>>>>>
> >>>>>> Umesh Sharad Shisode,
> >>>>>> M.Tech in Modeling and Simulation(2013-15),
> >>>>>> Centre for Modeling and Simulation,
> >>>>>> University of Pune.
> >>>>>>
> >>>>>> On Mon, May 18, 2015 at 7:31 PM, Junchao Zhang <jczhang at mcs.anl.gov
> >
> >>>>>> wrote:
> >>>>>>
> >>>>>>> Could not reproduce it with the latest MPICH. If the problem is
> not
> >>>>>>> specific to MPICH, you'd better move your question to other forums
> >> like
> >>>>>>> stackoverflow.
> >>>>>>>
> >>>>>>> $mpirun -n 2 ./test
> >>>>>>> Matrix A :
> >>>>>>>
> >>>>>>> 1 2 3 4
> >>>>>>> 1 2 3 4
> >>>>>>> 1 2 3 4
> >>>>>>> 1 2 3 4
> >>>>>>>
> >>>>>>> Vector b before broadcast:
> >>>>>>> 1.000000, 2.000000, 3.000000, 4.000000
> >>>>>>> Matrix A column : 4
> >>>>>>> after sending: lLim = 2 uLim = 4 for rank : 1
> >>>>>>> count = 8
> >>>>>>>
> >>>>>>> Matrix A column : 0for rank = 1
> >>>>>>> after receive: lLim = 2 uLim = 4 for rank : 1
> >>>>>>> Ncol after broadcasting = 4
> >>>>>>>
> >>>>>>>
> >>>>>>> --Junchao Zhang
> >>>>>>>
> >>>>>>> On Mon, May 18, 2015 at 6:33 AM, Umesh Shisode <
> ushisode1 at gmail.com>
> >>>>>>> wrote:
> >>>>>>>
> >>>>>>>> Hello Sir / Madam,
> >>>>>>>>
> >>>>>>>> This is Umesh Sharad Shisode, pursuing Masters in Modeling and
> >>>>>>>> Simulation, at Centre for Modeling and Simulation, Pune
> University.
> >> I am in
> >>>>>>>> the final stage of my course. My Masters Thesis title is :
> >>>>>>>>
> >>>>>>>> Development of Conjugate Gradient solver in OpenFOAM / CPP
> using
> >>>>>>>> MPI
> >>>>>>>>
> >>>>>>>> I am now doing MPI part of my project and facing some problems
> with
> >>>>>>>> MPI functions syntax. I am trying to use CPP class object with MPI
> >>>>>>>> functions but it is giving some error. Which I don't understand.
> >>>>>>>>
> >>>>>>>> Operating system : LINUX
> >>>>>>>> Programming Language : CPP
> >>>>>>>>
> >>>>>>>> Commands I am using are :
> >>>>>>>>
> >>>>>>>> > mpic++ main.cpp -o result
> >>>>>>>> > mpirun -np 2 result
> >>>>>>>>
> >>>>>>>> Please help me to sort out this issue . I am attaching herewith
> zip
> >>>>>>>> file containing the code which I want to parallelize with the png
> >> file
> >>>>>>>> containing error. Waiting for your reply. Thanks in advance.
> >>>>>>>>
> >>>>>>>> Regards,
> >>>>>>>>
> >>>>>>>> Umesh Sharad Shisode,
> >>>>>>>> M.Tech in Modeling and Simulation(2013-15),
> >>>>>>>> Centre for Modeling and Simulation,
> >>>>>>>> University of Pune.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> _______________________________________________
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> >>>>>>>
> >>>>>>>
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