[mpich-discuss] Error while using MPI platform with CPP program

Wed May 20 05:37:50 CDT 2015

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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>>>>
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