StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

POHow allocate larger matrix?
primarykey
Id
17844559
data
AcceptedAnswerId
0
AnswerCount
0
ClosedDate
2013-07-25T08:44:53.893
CommentCount
10
CommunityOwnedDate
CreationDate
2013-07-24T20:50:36.270
FavoriteCount
0
LastActivityDate
2013-07-24T23:47:12.460
LastEditDate
2013-07-24T23:47:12.460
LastEditorUserId
15168
OwnerUserId
2616024
ParentId
0
PostTypeId
1
Score
0
ViewCount
48
LastEditorDisplayName
text
Body
I'm new in programming MPI and my difficulty is allocate dynamically a larger matrix. The problem that appeared was: Line command: <pre><code>$ mpicc teste5.c -o teste5 $ mpirun -np 2 teste5 [frontend:13283] *** Process received signal *** -------------------------------------------------------------------------- mpirun noticed that process rank 1 with PID 13283 on node frontend exited on signal 11 (Segmentation fault). -------------------------------------------------------------------------- $ </code></pre> Code: <pre><code>#include "mpi.h" #include <stdio.h> #include <stdlib.h> #define max 5000 int main (int argc, char *argv[]){ int numtasks, /* number of tasks in partition */ taskid, /* a task identifier */ numworkers, /* number of worker tasks */ source, /* task id of message source */ dest, /* task id of message destination */ i, j, k; /* misc */ // float a[max][max],aux_a[max][max]; /* See comments */ float **a, **aux_a; MPI_Status status; MPI_Init(&argc,&argv); MPI_Comm_rank(MPI_COMM_WORLD,&taskid); (MPI_COMM_WORLD,&numtasks); numworkers = numtasks-1; if (taskid == 0){ a = (float **) malloc (max * sizeof(float *)); for ( i = 0; i < max; i++ ) a[i] = (float*) malloc (max * sizeof(float)); aux_a = (float **) malloc (max * sizeof(float *)); for ( i = 0; i < max; i++ ) aux_a[i] = (float*) malloc (max * sizeof(float)); for (i=0; i<max; i++) for (j=0; j<max; j++) a[i][j]= i+1; for (dest=1; dest<=numworkers; dest++){ MPI_Send(&a, max*max, MPI_FLOAT, dest, 1, MPI_COMM_WORLD); } for (i=1; i<=numworkers; i++){ source = i; MPI_Recv(&aux_a, max*max, MPI_FLOAT, source, 1, MPI_COMM_WORLD, &status); } printf("******************************************************\n"); printf("Result Matrix:\n"); for (i=0; i<max; i++){ printf("\n"); for (j=0; j<max; j++) printf("%6.2f ", aux_a[i][j]); } printf("\n******************************************************\n"); printf ("Done.\n"); } if (taskid > 0) { a = (float **) malloc (max * sizeof(float *)); for ( i = 0; i < max; i++ ) a[i] = (float*) malloc (max * sizeof(float)); aux_a = (float **) malloc (max * sizeof(float *)); for ( i = 0; i < max; i++ ) aux_a[i] = (float*) malloc (max * sizeof(float)); MPI_Recv(&a, max*max, MPI_FLOAT, 0, 1, MPI_COMM_WORLD, &status); for (i=0; i<max; i++) for (j=0; j<max; j++) aux_a[i][j] = a[i][j]; MPI_Send(&aux_a, max*max, MPI_FLOAT, 0, 1, MPI_COMM_WORLD); } MPI_Finalize(); } </code></pre> Can you help me?
Tags
<c><mpi><dynamic-memory-allocation>
Title
How allocate larger matrix?
singulars
PostAcceptedAnswerId
1. This table or related slice is empty.
PostParentId
1. This table or related slice is empty.
PostTypePostTypeId
1. PTQuestion
UserLastEditorUserId
1. USJonathan Leffler
UserOwnerUserId
1. USPedro A.
plurals
PostLinksPostIdRelatedPostId
1. PL
 singulars
 LinkTypeLinkTypeId
 LTLinked
2. PL
 singulars
 LinkTypeLinkTypeId
 LTDuplicate
PostLinksRelatedPostIdPostId
1. This table or related slice is empty.
PostsAcceptedAnswerId
1. This table or related slice is empty.
PostsParentIdCreationDate
1. This table or related slice is empty.
VotesPostIdCreationDate
1. This table or related slice is empty.
CommentsPostId

Querying!

Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.