Question

尝试编译和编程，这将帮助我对机器之间的消息传递进行基准测试，但我得到31个编译器错误：（

这些是我收到的错误：

PingPong.java:9: error: cannot find symbol
        my_pe = MPI.COMM_WORLD.Rank();
        ^
  symbol:   variable my_pe
  location: class PingPong
PingPong.java:10: error: cannot find symbol
        npes = MPI.COMM_WORLD.Size();
        ^
  symbol:   variable npes
  location: class PingPong
PingPong.java:11: error: cannot find symbol
        for (log2nbyte = 0; log2nbyte <= LOG2N_MAX; ++log2nbyte) {
             ^
  symbol:   variable log2nbyte
  location: class PingPong
PingPong.java:11: error: cannot find symbol
        for (log2nbyte = 0; log2nbyte <= LOG2N_MAX; ++log2nbyte) {
                            ^
  symbol:   variable log2nbyte
  location: class PingPong
PingPong.java:11: error: cannot find symbol
        for (log2nbyte = 0; log2nbyte <= LOG2N_MAX; ++log2nbyte) {
                                         ^
  symbol:   variable LOG2N_MAX
  location: class PingPong
PingPong.java:11: error: cannot find symbol
        for (log2nbyte = 0; log2nbyte <= LOG2N_MAX; ++log2nbyte) {
                                                      ^
  symbol:   variable log2nbyte
  location: class PingPong
PingPong.java:12: error: cannot find symbol
            nbyte = (1 << log2nbyte);
            ^
  symbol:   variable nbyte
  location: class PingPong
PingPong.java:12: error: cannot find symbol
            nbyte = (1 << log2nbyte);
                          ^
  symbol:   variable log2nbyte
  location: class PingPong
PingPong.java:13: error: cannot find symbol
            byte A[] = new byte[nbyte];
                                ^
  symbol:   variable nbyte
  location: class PingPong
PingPong.java:14: error: cannot find symbol
            for (j_pe = 1; j_pe <= npes - 1; ++j_pe) {
                 ^
  symbol:   variable j_pe
  location: class PingPong
PingPong.java:14: error: cannot find symbol
            for (j_pe = 1; j_pe <= npes - 1; ++j_pe) {
                           ^
  symbol:   variable j_pe
  location: class PingPong
PingPong.java:14: error: cannot find symbol
            for (j_pe = 1; j_pe <= npes - 1; ++j_pe) {
                                   ^
  symbol:   variable npes
  location: class PingPong
PingPong.java:14: error: cannot find symbol
            for (j_pe = 1; j_pe <= npes - 1; ++j_pe) {
                                               ^
  symbol:   variable j_pe
  location: class PingPong
PingPong.java:16: error: cannot find symbol
                tf[0] = MPI.Wtime();
                ^
  symbol:   variable tf
  location: class PingPong
PingPong.java:17: error: cannot find symbol
                for (n_pp = 0; n_pp < PINGPONGS; n_pp++) {
                     ^
  symbol:   variable n_pp
  location: class PingPong
PingPong.java:17: error: cannot find symbol
                for (n_pp = 0; n_pp < PINGPONGS; n_pp++) {
                               ^
  symbol:   variable n_pp
  location: class PingPong
PingPong.java:17: error: cannot find symbol
                for (n_pp = 0; n_pp < PINGPONGS; n_pp++) {
                                      ^
  symbol:   variable PINGPONGS
  location: class PingPong
PingPong.java:17: error: cannot find symbol
                for (n_pp = 0; n_pp < PINGPONGS; n_pp++) {
                                                 ^
  symbol:   variable n_pp
  location: class PingPong
PingPong.java:18: error: cannot find symbol
                    if (my_pe == j_pe) {
                        ^
  symbol:   variable my_pe
  location: class PingPong
PingPong.java:18: error: cannot find symbol
                    if (my_pe == j_pe) {
                                 ^
  symbol:   variable j_pe
  location: class PingPong
PingPong.java:19: error: cannot find symbol
                        MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, 0, 10);
                                                  ^
  symbol:   variable nbyte
  location: class PingPong
PingPong.java:20: error: cannot find symbol
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, 0, 2
0);
                        ^
  symbol:   variable status
  location: class PingPong
PingPong.java:20: error: cannot find symbol
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, 0, 2
0);
                                                           ^
  symbol:   variable nbyte
  location: class PingPong
PingPong.java:22: error: cannot find symbol
                    if (my_pe == 0) {
                        ^
  symbol:   variable my_pe
  location: class PingPong
PingPong.java:23: error: cannot find symbol
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, j_pe
, 10);
                        ^
  symbol:   variable status
  location: class PingPong
PingPong.java:23: error: cannot find symbol
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, j_pe
, 10);
                                                           ^
  symbol:   variable nbyte
  location: class PingPong
PingPong.java:23: error: cannot find symbol
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, j_pe
, 10);
                                                                            ^
  symbol:   variable j_pe
  location: class PingPong
PingPong.java:24: error: cannot find symbol
                        MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, j_pe, 20);
                                                  ^
  symbol:   variable nbyte
  location: class PingPong
PingPong.java:24: error: cannot find symbol
                        MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, j_pe, 20);
                                                                   ^
  symbol:   variable j_pe
  location: class PingPong
PingPong.java:27: error: cannot find symbol
                tf[ns + 1] = MPI.Wtime();
                ^
  symbol:   variable tf
  location: class PingPong
PingPong.java:27: error: cannot find symbol
                tf[ns + 1] = MPI.Wtime();
                   ^
  symbol:   variable ns
  location: class PingPong
31 errors

这是我想编译的代码：

    public static void main(String[] args) throws MPIException {

        MPI.Init(args);
        my_pe = MPI.COMM_WORLD.Rank();
        npes = MPI.COMM_WORLD.Size();
        for (log2nbyte = 0; log2nbyte <= LOG2N_MAX; ++log2nbyte) {
            nbyte = (1 << log2nbyte);
            byte A[] = new byte[nbyte];
            for (j_pe = 1; j_pe <= npes - 1; ++j_pe) {
                MPI.COMM_WORLD.Barrier();
                tf[0] = MPI.Wtime();
                for (n_pp = 0; n_pp < PINGPONGS; n_pp++) {
                    if (my_pe == j_pe) {
                        MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, 0, 10);
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, 0, 20);
                    }
                    if (my_pe == 0) {
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, j_pe, 10);
                        MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, j_pe, 20);
                    }
                }
                tf[ns + 1] = MPI.Wtime();
            }
        }
        MPI.Finalize();
    }
}

任何想法为什么会提起这些错误，这是我第一次尝试在CMD上编码而不是使用netbeans，所以我对错误感到困惑

EDIT ::

是的，代码来自谷歌，我希望它能帮助我理解它是如何工作的，所以我可以使用其他一些代码的位

这就是目前的情况：

import mpi.*;

class PingPong {

    public static int j_pe;
public static int npes;
public static int log2nbyte;
public static int nbyte;
public static int LOG2N_MAX;
public static int PINGPONGS;
public static int n_pp;
public static int status;
public static int ns;

public static void main(String[] args) throws MPIException {

    int my_pe = 0;

    MPI.Init(args);
    my_pe = MPI.COMM_WORLD.Rank();
    npes = MPI.COMM_WORLD.Size();
    for (log2nbyte = 0; log2nbyte <= LOG2N_MAX; ++log2nbyte) {
        nbyte = (1 << log2nbyte);
        byte A[] = new byte[nbyte];
        for (j_pe = 1; j_pe <= npes - 1; ++j_pe) {
            MPI.COMM_WORLD.Barrier();
            tf[0] = MPI.Wtime();
            for (n_pp = 0; n_pp < PINGPONGS; n_pp++) {
                if (my_pe == j_pe) {
                    MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, 0, 10);
                    status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, 0, 20);
                }
                if (my_pe == 0) {
                    status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, j_pe, 10);
                    MPI.COMM_WORLD.Send(A, 0, nbyte, MPI.BYTE, j_pe, 20);
                }
            }
            tf[ns + 1] = MPI.Wtime();
        }
    }
    MPI.Finalize();
}

}

但我仍然遇到这些错误：

PingPong.java:29: error: cannot find symbol
                tf[0] = MPI.Wtime();
                ^
  symbol:   variable tf
  location: class PingPong
PingPong.java:33: error: incompatible types
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, 0, 2
0);
                                                    ^
  required: int
  found:    Status
PingPong.java:36: error: incompatible types
                        status = MPI.COMM_WORLD.Recv(A, 0, nbyte, MPI.BYTE, j_pe
, 10);
                                                    ^
  required: int
  found:    Status
PingPong.java:40: error: cannot find symbol
                tf[ns + 1] = MPI.Wtime();
                ^
  symbol:   variable tf
  location: class PingPong
4 errors

Answer 1

没有定义任何变量。看起来像经典的复制/粘贴定义变量并使用Eclipse。

Answer 2

您尚未声明变量。

声明所有这些变量，并在局部变量的情况下将它们初始化为默认值。

int my_pe = 0;

对所有其他变量执行相同操作。

31编译器错误:(

2 个答案: