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Finite-Difference Hyperbolic-Parabolic PDE Solver on Cartesian Grids
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MPIPartitionArray1D.c
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1 
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <basic.h>
9 #include <arrayfunctions.h>
10 #include <mpivars.h>
11 
26  void *m,
27  double *xg,
28  double *x,
29  int istart,
30  int iend,
31  int N_local,
32  int ghosts
33  )
34 {
35  MPIVariables *mpi = (MPIVariables*) m;
36  int ierr = 0;
37 #ifndef serial
38  MPI_Status status;
39 #endif
40 
41  /* xg should be non-null only on root */
42  if (mpi->rank && xg) {
43  fprintf(stderr,"Error in MPIPartitionArray1D(): global array exists on non-root processors (rank %d).\n",
44  mpi->rank);
45  ierr = 1;
46  }
47  if ((!mpi->rank) && (!xg)) {
48  fprintf(stderr,"Error in MPIPartitionArray1D(): global array is not allocated on root processor.\n");
49  ierr = 1;
50  }
51 
52  if (!mpi->rank) {
53  int proc;
54  for (proc = 0; proc < mpi->nproc; proc++) {
55  /* Find out the domain limits for each process */
56  int is,ie;
57  if (proc) {
58 #ifndef serial
59  MPI_Recv(&is,1,MPI_INT,proc,1442,mpi->world,&status);
60  MPI_Recv(&ie,1,MPI_INT,proc,1443,mpi->world,&status);
61 #endif
62  } else {
63  is = istart;
64  ie = iend;
65  }
66  int size = ie - is;
67  double *buffer = (double*) calloc (size, sizeof(double));
68  _ArrayCopy1D_((xg+is),buffer,size);
69  if (proc) {
70 #ifndef serial
71  MPI_Send(buffer,size,MPI_DOUBLE,proc,1539,mpi->world);
72 #endif
73  } else _ArrayCopy1D_(buffer,x,N_local);
74  free(buffer);
75  }
76 
77  } else {
78 #ifndef serial
79  /* Meanwhile, on other processes */
80  /* send local start and end indices to root */
81  MPI_Send(&istart,1,MPI_INT,0,1442,mpi->world);
82  MPI_Send(&iend ,1,MPI_INT,0,1443,mpi->world);
83  double *buffer = (double*) calloc (N_local, sizeof(buffer));
84  MPI_Recv(buffer,N_local,MPI_DOUBLE,0,1539,mpi->world,&status);
85  _ArrayCopy1D_(buffer,x,N_local);
86  free(buffer);
87 #endif
88  }
89  return(ierr);
90 }
int MPIPartitionArray1D(void *, double *, double *, int, int, int, int)
MPI related function definitions.
MPI_Comm world
#define _ArrayCopy1D_(x, y, size)
Some basic definitions and macros.
Contains macros and function definitions for common array operations.
Structure of MPI-related variables.