src/gromacs/utility/basenetwork.cpp

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  37 #include "gmxpre.h"
  38
  39 #include "basenetwork.h"
  40
  41 #include "config.h"
  42
  43 #include <climits>
  44 #include <cstdio>
  45 #include <cstdlib>
  46 #include <cstring>
  47
  48 #include "gromacs/utility/cstringutil.h"
  49 #include "gromacs/utility/fatalerror.h"
  50 #include "gromacs/utility/gmxmpi.h"
  51
  52 bool gmx_mpi_initialized()
  53 {
  54 #if !GMX_MPI
  55     return 0;
  56 #else
  57     int n;
  58     MPI_Initialized(&n);
  59
  60     return n != 0;
  61 #endif
  62 }
  63
  64 int gmx_node_num()
  65 {
  66 #if !GMX_MPI
  67     return 1;
  68 #else
  69 #if GMX_THREAD_MPI
  70     if (!gmx_mpi_initialized())
  71     {
  72         return 1;
  73     }
  74 #endif
  75     int i;
  76     (void) MPI_Comm_size(MPI_COMM_WORLD, &i);
  77     return i;
  78 #endif
  79 }
  80
  81 int gmx_node_rank()
  82 {
  83 #if !GMX_MPI
  84     return 0;
  85 #else
  86 #if GMX_THREAD_MPI
  87     if (!gmx_mpi_initialized())
  88     {
  89         return 0;
  90     }
  91 #endif
  92     int i;
  93     (void) MPI_Comm_rank(MPI_COMM_WORLD, &i);
  94     return i;
  95 #endif
  96 }
  97
  98 static int mpi_hostname_hash()
  99 {
 100     int hash_int;
 101
 102 #if GMX_LIB_MPI
 103     int  resultlen;
 104     char mpi_hostname[MPI_MAX_PROCESSOR_NAME];
 105
 106     /* This procedure can only differentiate nodes with different names.
 107      * Architectures where different physical nodes have identical names,
 108      * such as IBM Blue Gene, should use an architecture specific solution.
 109      */
 110     MPI_Get_processor_name(mpi_hostname, &resultlen);
 111
 112     /* The string hash function returns an unsigned int. We cast to an int.
 113      * Negative numbers are converted to positive by setting the sign bit to 0.
 114      * This makes the hash one bit smaller.
 115      * A 63-bit hash (with 64-bit int) should be enough for unique node hashes,
 116      * even on a million node machine. 31 bits might not be enough though!
 117      */
 118     hash_int = static_cast<int>(gmx_string_fullhash_func(mpi_hostname, gmx_string_hash_init));
 119     if (hash_int < 0)
 120     {
 121         hash_int -= INT_MIN;
 122     }
 123 #else
 124
 125     /* thread-MPI currently puts the thread number in the process name,
 126      * we might want to change this, as this is inconsistent with what
 127      * most MPI implementations would do when running on a single node.
 128      */
 129     hash_int = 0;
 130 #endif
 131
 132     return hash_int;
 133 }
 134
 135 int gmx_physicalnode_id_hash()
 136 {
 137     int hash = 0;
 138
 139     if (GMX_MPI)
 140     {
 141         hash = mpi_hostname_hash();
 142     }
 143
 144     if (debug)
 145     {
 146         fprintf(debug, "In gmx_physicalnode_id_hash: hash %d\n", hash);
 147     }
 148
 149     return hash;
 150 }
 151
 152 void gmx_broadcast_world(int size, void *buffer)
 153 {
 154 #if GMX_MPI
 155     MPI_Bcast(buffer, size, MPI_BYTE, 0, MPI_COMM_WORLD);
 156 #else
 157     GMX_UNUSED_VALUE(size);
 158     GMX_UNUSED_VALUE(buffer);
 159 #endif
 160 }
 161
 162 #if GMX_LIB_MPI
 163 void gmx_abort(int errorno)
 164 {
 165     MPI_Abort(MPI_COMM_WORLD, errorno);
 166     std::abort();
 167 }
 168 #endif