MPI下执行出现的奇怪问题

两台机器上面执行同样的命令，同样的程序，得出截然相反的结果， 这是神马情况?

node11上面:

1. 执行 mpiexec -np 16 piC , 报错：

[proxy:0:0@node11] HYDU_create_process (./utils/launch/launch.c:69): execvp error on file piC (No such file or directory)

2. 改为执行piexec -np 16 ./piC ，程序正常执行.

node12上面:

1. 执行 mpiexec -np 16 ./piC ,报错:

[proxy:0:0@node11] HYDU_create_process (./utils/launch/launch.c:69): execvp error on file ./piC (No such file or directory)

2. 执行 mpiexec -np 16 piC, 正常执行.

两台机器上面都是同样的程序，执行同样的命令，得到了截然相反的结果，让哥情何以堪.....

注意到报错的都是node11的问题， 解决如下:

1. node12上面的问题是因为node11上没有同名的目录，执行文件又找错了, node11上面则是因为exec的执行顺序:

http://linux.about.com/library/cmd/blcmdl3_execvp.htm

The functions execlp and execvp will duplicate the actions of the shell in searching for an executable file if the specified file name does not contain a slash (/) character. The search path is the path specified in the environment by the PATH variable. If this variable isn't specified, the default path ``:/bin:/usr/bin'' is used. In addition, certain errors are treated specially.

我勒个去。。。。。