117 | | ym000@bio001:~$ mpiexec -n 12 ./test1 |
118 | | }}} |
| 117 | ym24@bio001:~$ mpiexec -n 12 ./test1 |
| 118 | }}} |
| 119 | * here is test2.c |
| 120 | {{{ |
| 121 | ym24@bio001:~$ cat << EOF > test2.c |
| 122 | #include <mpi.h> |
| 123 | #include <stdio.h> |
| 124 | main(int argc,char **argv) { |
| 125 | int n, myrank, numprocs; |
| 126 | MPI_Status status; |
| 127 | MPI_Init(&argc,&argv); |
| 128 | MPI_Comm_size(MPI_COMM_WORLD,&numprocs); |
| 129 | MPI_Comm_rank(MPI_COMM_WORLD,&myrank); |
| 130 | |
| 131 | /* node 0 will send the first message */ |
| 132 | if(myrank == 0) { |
| 133 | n = myrank; |
| 134 | MPI_Send(&n, 1, MPI_INT, 1, 99, MPI_COMM_WORLD); |
| 135 | printf("[Ndde %d]「%d」 >> [Node %d]\n\n", myrank, n, myrank+1); |
| 136 | } |
| 137 | |
| 138 | /* node 1 to node n-2 will send message to the next node */ |
| 139 | if(myrank>0 && myrank<numprocs-1) { |
| 140 | MPI_Recv(&n, 1, MPI_INT, myrank-1, 99, MPI_COMM_WORLD, &status); |
| 141 | printf("[Node %d] << 「%d」[Node %d]\n", myrank, n, status.MPI_SOURCE); |
| 142 | n = myrank; MPI_Send(&n, 1, MPI_INT, myrank+1, 99, MPI_COMM_WORLD); |
| 143 | printf("[Ndde %d]「%d」 >> [Node %d]\n\n", myrank, n, myrank+1); |
| 144 | } |
| 145 | |
| 146 | /* the final node n-1 will not send any message but receive*/ |
| 147 | if(myrank==numprocs-1) { |
| 148 | MPI_Recv(&n, 1, MPI_INT, myrank-1, 99, MPI_COMM_WORLD, &status); |
| 149 | printf("[Node %d] << 「%d」[Node %d]\n", myrank, n, status.MPI_SOURCE); |
| 150 | } |
| 151 | |
| 152 | MPI_Finalize(); |
| 153 | } |
| 154 | EOF |
| 155 | }}} |
| 156 | * 用 mpicc 編譯 test2.c |
| 157 | {{{ |
| 158 | ym24@bio001:~$ mpicc -o test2 test2.c |
| 159 | }}} |
| 160 | * 用 mpiexec 執行 test2 程式 |
| 161 | {{{ |
| 162 | ym24@bio001:~$ mpiexec -n 12 ./test2 |
| 163 | }}} |
| 164 | * here is test3.c |
| 165 | {{{ |
| 166 | ym24@bio001:~$ cat << EOF > test3.c |
| 167 | /* Program: |
| 168 | * 每個 node 將訊息傳送給 node 0,由,node 0 統一印出 |
| 169 | * History: |
| 170 | * 2008-06-12 BETA |
| 171 | * 2008-06-17 更改顯示方式,並增加註解 |
| 172 | */ |
| 173 | |
| 174 | #include <stdio.h> |
| 175 | #include <mpi.h> |
| 176 | #include <string.h> |
| 177 | |
| 178 | main(int argc, char **argv) |
| 179 | { |
| 180 | int myrank, i, numprocs; |
| 181 | char message[20]; |
| 182 | MPI_Status status; |
| 183 | MPI_Init(&argc, &argv); |
| 184 | MPI_Comm_size(MPI_COMM_WORLD, &numprocs); |
| 185 | MPI_Comm_rank(MPI_COMM_WORLD, &myrank); |
| 186 | |
| 187 | /* Node 0 will do the following */ |
| 188 | if(myrank == 0) |
| 189 | { |
| 190 | /* receive messages from other nodes */ |
| 191 | for(i = 1; i < numprocs; i++) |
| 192 | { |
| 193 | MPI_Recv(message, 20, MPI_CHAR, i, 99, MPI_COMM_WORLD, &status); |
| 194 | printf("[Node 0] << 「%s」[Node %d] \n", message, status.MPI_SOURCE); |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | /* other Nodes will do the following */ |
| 199 | if(myrank != 0) |
| 200 | { |
| 201 | /* send node's rank to Node 0 */ |
| 202 | sprintf(message, "[%d]", myrank); |
| 203 | MPI_Send(message, 20, MPI_CHAR, 0, 99, MPI_COMM_WORLD); |
| 204 | printf("[Node %d]「%s」 >> [Node 0]\n", myrank, message); |
| 205 | } |
| 206 | MPI_Finalize(); |
| 207 | } |
| 208 | EOF |
| 209 | }}} |
| 210 | * 用 mpicc 編譯 test3.c |
| 211 | {{{ |
| 212 | ym24@bio001:~$ mpicc -o test2 test3.c |
| 213 | }}} |
| 214 | * 用 mpiexec 執行 test3 程式 |
| 215 | {{{ |
| 216 | ym24@bio001:~$ mpiexec -n 12 ./test3 |
| 217 | }}} |
| 218 | * here is test4 |
| 219 | {{{ |
| 220 | ym24@bio001:~$ cat << EOF > test4.c |
| 221 | /* Program: |
| 222 | * mpich_example 內建範例,計算 pi 。 |
| 223 | * History: |
| 224 | * 2008-04-11 BETA |
| 225 | * 2008-06-19 增加可重複輸入欲計算之精準度 |
| 226 | * 2008-06-23 加入 MPI_Barrier 以確保每個 node 在接受 n 後才執行 |
| 227 | */ |
| 228 | |
| 229 | #include "mpi.h" |
| 230 | #include <stdio.h> |
| 231 | #include <math.h> |
| 232 | #include <time.h> |
| 233 | |
| 234 | double f( double ); |
| 235 | double f( double a ) |
| 236 | { |
| 237 | return (4.0 / (1.0 + a*a)); |
| 238 | } |
| 239 | |
| 240 | int main( int argc, char *argv[]) |
| 241 | { |
| 242 | int done = 0, n, myid, numprocs, i=0; |
| 243 | double PI25DT = 3.141592653589793238462643; |
| 244 | double mypi, pi, h, sum, x; |
| 245 | double startwtime = 0.0, endwtime; |
| 246 | int namelen; |
| 247 | char processor_name[MPI_MAX_PROCESSOR_NAME]; |
| 248 | MPI_Init(&argc,&argv); |
| 249 | MPI_Comm_size(MPI_COMM_WORLD,&numprocs); |
| 250 | MPI_Comm_rank(MPI_COMM_WORLD,&myid); |
| 251 | MPI_Get_processor_name(processor_name,&namelen); |
| 252 | fprintf(stderr,"Process %d on %s\n", |
| 253 | myid, processor_name); |
| 254 | n = 0; |
| 255 | while (!done) |
| 256 | { |
| 257 | /* 由 node 0 將使用者輸入的值送給其它的 node */ |
| 258 | if (myid == 0) |
| 259 | { |
| 260 | printf("Enter the number of intervals: (0 quits) "); |
| 261 | scanf("%d", &n); |
| 262 | startwtime = MPI_Wtime(); |
| 263 | } |
| 264 | |
| 265 | /* 這非常重要,所有的 node 必需在此同步,才可以收到使用者輸入的 n */ |
| 266 | MPI_Barrier(MPI_COMM_WORLD); |
| 267 | |
| 268 | /* 將 n 送給其它的 node */ |
| 269 | MPI_Bcast(&n, 1, MPI_INT, 0, MPI_COMM_WORLD); |
| 270 | if (n == 0) |
| 271 | done = 1; |
| 272 | else |
| 273 | { |
| 274 | |
| 275 | /* 此為計算 pi 的演算法 */ |
| 276 | h = 1.0 / (double) n; |
| 277 | sum = 0.0; |
| 278 | for (i = myid + 1; i <= n; i += numprocs) |
| 279 | { |
| 280 | x = h * ((double)i - 0.5); |
| 281 | sum += f(x); |
| 282 | } |
| 283 | mypi = h * sum; |
| 284 | |
| 285 | /* 將算完的結果傳給 node 0 加總 */ |
| 286 | MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD); |
| 287 | if (myid == 0) |
| 288 | { |
| 289 | printf("pi is approximately %.16f, Error is %.16f\n", |
| 290 | pi, fabs(pi - PI25DT)); |
| 291 | endwtime = MPI_Wtime(); |
| 292 | printf("wall clock time = %f\n", |
| 293 | endwtime-startwtime); |
| 294 | } |
| 295 | } |
| 296 | } |
| 297 | MPI_Finalize(); |
| 298 | return 0; |
| 299 | } |
| 300 | EOF |
| 301 | }}} |
| 302 | * 用 mpicc 編譯 test4.c |
| 303 | {{{ |
| 304 | ym24@bio001:~$ mpicc -o test2 test4.c |
| 305 | }}} |
| 306 | * 用 mpiexec 執行 test4 程式 |
| 307 | {{{ |
| 308 | ym24@bio001:~$ mpiexec -n 12 ./test4 |
| 309 | }}} |