Re: [OMPI users] MPI_Type_struct for structs with dynamic arrays

[George Bosilca]

Jitendra,




Try the following
MPI_Get_address(&parentPop[0].indiv[0].intvar[0], &disp[0]);
instead of
MPI_Get_address(&parentPop[0].indiv[0].intvar, &disp[0]);





  george.

On Aug 11, 2008, at 1:07 AM, Jitendra Kumar wrote:

There is a problem with the addresses you provide to MPI_Type_struct. For all arrays instead of giving the pointer to the array, you provide a pointer to the pointer in the individual struct. Please note the [0] after the array name. Please do the same to all arrays and I think the MPI_Type_struct will do the rest. Btw, you dont have to substract the disp[0] from all addresses. Instead you can use MPI_BOTTOM and all your addresses can be absolute.

Hi,
I am trying to use MPI derived datatype doutines for sending a struct
which contains dynamically allocated arrays. I tried implementing it
using MPI_Type_struct. It doesn't throws any error but messages being
received (of the declared datatype) aren't correct. Some memory
corruption seems to be going on as the value of 'rank' at receive end

struct and implementation of the derived datatype.
I am not sure where things are going wrong. I would highly appreciate

of MPI_Type_struct considering that  frequent communication of these
structs are needed?

Thanks,
Jitendra

The struct looks like this:
    51 typedef struct
    52 {
    53     int *intvar;
    54     double *realvar;
    55     double *binvar;
    56     int **gene;
    57
    58     double *obj;
    59     double *constr;
    60     double constr_violation;
    61     double crowd_dist;
    62     int rank;
    63     double *strategyParameter;
    64 }
    65 individual;

Implementation of the derived datatype:

   483         blockcounts[0] = parentPop[0].numInteger;
   484         blockcounts[1] = parentPop[0].numReal;
   485         blockcounts[2] = parentPop[0].numBinary;
   486         sum = 0;
   487         for(i=0; i<parentPop[0].numBinary; i++)
   488         {
   489             sum = sum + parentPop[0].nbits[i];
   490         }
   491
   492         blockcounts[3] = sum;
   493         blockcounts[4] = parentPop[0].nobj;
   494         blockcounts[5] = parentPop[0].ncon;
   495         blockcounts[6] = 1;
   496         blockcounts[7] = 1;
   497         blockcounts[8] = 1;
   498         blockcounts[9] = parentPop[0].numInteger +
parentPop[0].numReal;

   506         types[0] = MPI_INT;
   507         types[1] = MPI_DOUBLE;
   508         types[2] = MPI_DOUBLE;
   509         types[3] = MPI_INT;
   510         types[4] = MPI_DOUBLE;
   511         types[5] = MPI_DOUBLE;
   512         types[6] = MPI_DOUBLE;
   513         types[7] = MPI_DOUBLE;
   514         types[8] = MPI_INT;
   515         types[9] = MPI_DOUBLE;
   516

   518         printf("parentpop.indiv0 %ld disp %ld (%ld)\n",
&parentPop[0].indiv[0], disp, disp[0]);

   520         printf("disp 1 %ld\n", disp[1]);

   522         printf("disp 2 %ld\n", disp[2]);
   523         MPI_Get_address(&parentPop[0].indiv[0].gene, &disp[3]);
   524         MPI_Get_address(&parentPop[0].indiv[0].obj, &disp[4]);

&disp[6]);
   527         MPI_Get_address(&parentPop[0].indiv[0].crowd_dist,
&disp[7]);
   528         MPI_Get_address(&parentPop[0].indiv[0].rank, &disp[8]);
   529
MPI_Get_address(&parentPop[0].indiv[0].strategyParameter, &disp[9]);
   530         base = disp[0];
   531         for(i=0; i<10; i++)
   532         {
   533             disp[i] -= base;
   534         }
   535
   536         MPI_Type_create_struct(10, blockcounts, disp, types,
&Individual);
   537
   538         /* Check that the datatype has correct extent */
   539         MPI_Type_extent(Individual, &extent);
   540         if(extent != sizeof(individual))
   541         {
   542             MPI_Datatype indold = Individual;
   543             MPI_Type_create_resized(indold, 0,
sizeof(individual), &Individual);
   544             MPI_Type_free(&indold);
   545         }
   546         MPI_Type_commit(&Individual);

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are changed to 0 right after the receive . Below are the snippets of my any pointers or suggestions. Is there any better alternative way instead 517 MPI_Get_address(&parentPop[0].indiv[0].intvar, &disp[0]); 519 MPI_Get_address(&parentPop[0].indiv[0].realvar, &disp[1]); 521 MPI_Get_address(&parentPop[0].indiv[0].binvar, &disp[2]); 525 MPI_Get_address(&parentPop[0].indiv[0].constr, &disp[5]); 526 MPI_Get_address(&parentPop[0].indiv[0].constr_violation,

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