Some examples of mpi

C/Advanced/Parallel/MPI/Praticas/mpi_bug1.c

@@ -0,0 +1,44 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+  int numprocs, rank, tag, num, i;
+  MPI_Status status;
+
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+  if (numprocs != 2) {
+    MPI_Finalize();
+    if (rank == 0)
+      printf("Run the program with 2 processes!\n");
+    exit(0);
+  }
+
+  printf("Proc %d starting...\n", rank);
+  tag = 0;
+  if (rank == 0) {
+    for (i = 0; i < 10; i++) {
+      num = i * 10;
+      MPI_Send(&num, 1, MPI_INT, 1, tag, MPI_COMM_WORLD);
+      printf("Proc %d sent int '%d'\n", rank, num);
+    }
+  }
+  if (rank == 1) {
+    for (i = 0; i < 10; i++) {
+      MPI_Recv(&num, 1, MPI_INT, 0, tag, MPI_COMM_WORLD, &status);
+      printf("Proc %d received int '%d'\n", rank, num);
+    }
+  }
+
+  MPI_Finalize();
+}
+
+/** 
+
+  PROBLEMA: Linha 31 tipo da menssagem errado!
+  CORREÇAO: Mudar MPI_CHAR para MPI_INT!
+
+*/

C/Advanced/Parallel/MPI/Praticas/mpi_bug2.c

@@ -0,0 +1,48 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[]) {
+  int numprocs, rank, tag, count;
+  char inmsg, outmsg;
+  MPI_Status status;
+
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+  if (numprocs != 2) {
+    MPI_Finalize();
+    if (rank == 0)
+      printf("Run the program with 2 processes!\n");
+    exit(0);
+  }
+
+  printf("Proc %d starting...\n", rank);
+  tag = rank;
+  if (rank == 0) {
+    outmsg = 'x';
+    MPI_Send(&outmsg, 1, MPI_CHAR, 1, tag, MPI_COMM_WORLD);
+    printf("Proc %d sent char '%c'\n", rank, outmsg);
+    MPI_Recv(&inmsg, 1, MPI_CHAR, 1, tag, MPI_COMM_WORLD, &status);
+    printf("Proc %d received char '%c'\n", rank, inmsg);
+  } else if (rank == 1) {
+    outmsg = 'y';
+    MPI_Recv(&inmsg, 1, MPI_CHAR, 0, 0, MPI_COMM_WORLD, &status);
+    printf("Proc %d received char '%c'\n", rank, inmsg);
+    MPI_Send(&outmsg, 1, MPI_CHAR, 0, 0, MPI_COMM_WORLD);
+    printf("Proc %d sent char '%c'\n", rank, outmsg);
+  }
+  MPI_Get_count(&status, MPI_CHAR, &count);
+  printf("Proc %d received %d char(s) from proc %d with tag %d\n",
+	 rank, count, status.MPI_SOURCE, status.MPI_TAG);
+
+  MPI_Finalize();
+}
+
+/*
+
+  PROBLEMA: Ambos os processos ficam bloqueados no MPI_RECV 
+  CORREÇAO: No Revc e Send do processo 1 mudar a tag para 0
+
+*/

C/Advanced/Parallel/MPI/Praticas/mpi_bug3.c

@@ -0,0 +1,59 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define MSGSIZE 34000  // try with different sizes!
+
+int main(int argc, char *argv[]) { 
+  int numprocs, rank, tag, src, dest, count, i;
+  char data[MSGSIZE];
+
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+  if (numprocs != 2) {
+    MPI_Finalize();
+    if (rank == 0)
+      printf("Run the program with 2 processes!\n");
+    exit(0);
+  }
+
+  printf("Proc %d starting...\n", rank);
+  tag = 0;
+  dest = 1;
+  src = 0;
+  count = 0;
+  if (rank == 0) {
+    for (i = 0; i < MSGSIZE; i++)
+      data[i] = 'x';
+    while (count < MSGSIZE) {
+      MPI_Send(data, MSGSIZE, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
+      count ++;
+      printf("Sent message number %d to proc %d...\n", count, dest);
+    }
+  }
+  if (rank == 1) {
+    while (count < MSGSIZE) {
+      MPI_Recv(data, MSGSIZE, MPI_CHAR, src, tag, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
+      count++;
+      printf("Received message number %d from proc %d...\n", count, src);
+      //sleep(1);
+    }
+    for(i=0; i<MSGSIZE; i++) {
+      printf("%c%d", data[i], i);
+    }
+    printf("\n");
+  }
+
+  MPI_Finalize();
+}
+
+/*
+
+  PROBLEMA: Loop infinitos nos dois processos
+  CORREÇAO: condiçao de paragem
+
+
+*/

C/Advanced/Parallel/MPI/Praticas/mpi_bug4.c

@@ -0,0 +1,48 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define SIZE 4
+
+int main(int argc, char *argv[]) {
+  int numprocs, rank, tag, src, dest, i;
+  float a[SIZE][SIZE] = { 1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  7.0,  8.0,
+                          9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0 };
+  float b[SIZE];
+  MPI_Datatype rowtype;
+
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+ if (numprocs != SIZE) {
+    MPI_Finalize();
+    if (rank == 0)
+      printf("Run the program with %d processes!\n", SIZE);
+    exit(0);
+  }
+
+  printf("Proc %d starting...\n", rank);
+  tag = 0;
+  src = 0;
+
+  MPI_Type_contiguous(SIZE, MPI_FLOAT, &rowtype);
+  MPI_Type_commit(&rowtype);
+
+  if (rank == 0) {   
+    for (i = 0; i < numprocs; i++)
+      MPI_Send(&a[i][0], 1, rowtype, i, tag, MPI_COMM_WORLD);
+  }
+  MPI_Recv(b, SIZE, rowtype, src, tag, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
+  printf("Proc %d received b = %3.1f %3.1f %3.1f %3.1f\n", rank, b[0], b[1], b[2], b[3]);
+
+  MPI_Type_free(&rowtype);
+  MPI_Finalize();
+}
+
+/*
+
+  PROBLEMA: Processadores != 0 nao sabiam o que era o rowtype, ou seja, nao tava inicializado
+  CORREÇAO: Meter o MPI_Type_* para fora do rank 0 para que todos soubessem o que era o tipo rowtype
+
+*/

C/Advanced/Parallel/MPI/Praticas/mpi_bug5.c

@@ -0,0 +1,51 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define SIZE 4
+
+int main(int argc, char *argv[]) {
+  int numprocs, rank, tag, src, dest, i, blocklengths[2], displacements[2];
+  float a[SIZE][SIZE] = { 1.0,  2.0,  3.0,  4.0,  5.0,  6.0,  7.0,  8.0,
+                          9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0};
+  float b[SIZE];
+  MPI_Datatype indextype;
+
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+ if (numprocs != SIZE) {
+    MPI_Finalize();
+    if (rank == 0)
+      printf("Run the program with %d processes!\n", SIZE);
+    exit(0);
+  }
+
+  printf("Proc %d starting...\n", rank);
+  tag = 0;
+  src = 0;
+  blocklengths[0] = 2;
+  blocklengths[1] = 3;
+  displacements[0] = 5;
+  displacements[1] = 12;
+  MPI_Type_indexed(2, blocklengths, displacements, MPI_FLOAT, &indextype);
+  MPI_Type_commit(&indextype);
+  if (rank == 0)
+    for (i = 0; i < numprocs; i++){
+      MPI_Send(a, 1, indextype, i, tag, MPI_COMM_WORLD);
+      printf("Proc %d sending info...\n", rank);
+    }
+  MPI_Recv(b, SIZE, indextype, src, tag, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
+  printf("Proc %d received b = %3.1f %3.1f %3.1f %3.1f\n", rank, b[0], b[1], b[2], b[3]);
+
+  MPI_Type_free(&indextype);
+  MPI_Finalize();
+}
+
+/*
+  PROBLEMA: Tipos?
+  CORREÇAO: ???
+
+
+*/

C/Advanced/Parallel/MPI/Praticas/mpi_bug6.c

@@ -0,0 +1,45 @@
+#include <mpi.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define REQS 1000
+#define DISP 100
+
+int main(int argc, char *argv[]) {
+  int numprocs, rank, tag, src, dest, num, offset, i;
+  MPI_Request reqs[4 * REQS];
+
+  MPI_Init(&argc, &argv);
+  MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
+  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+ if (numprocs != 2) {
+    MPI_Finalize();
+    if (rank == 0)
+      printf("Run the program with 2 processes!\n");
+    exit(0);
+  }
+
+  printf("Proc %d starting...\n", rank);
+  MPI_Barrier(MPI_COMM_WORLD);
+  tag = 0;
+  if (rank == 0) {
+    src = 1;
+    offset = 0;
+  } else {
+    src = 0;
+    offset = 2 * REQS;
+  }
+  dest = src;
+  num = 1;
+  for (i = 1; i <= REQS; i++) {
+    MPI_Isend(&num, 1, MPI_INT, dest, tag, MPI_COMM_WORLD, &reqs[offset]);
+    MPI_Irecv(&num, 1, MPI_INT, src, tag, MPI_COMM_WORLD, &reqs[offset + 1]);
+    offset += 2;
+    if (i % DISP == 0)
+      printf("Proc %d has done %d isends/irecvs\n", rank, i);
+  }
+  MPI_Waitall(2 * REQS, reqs, MPI_STATUS_IGNORE);
+
+  MPI_Finalize();
+}