Comments for Nine Rivers

Comment on Subversion+websvn on Debian by Gamabounta

Gamabounta — Sat, 24 Jul 2010 15:20:02 +0000

Hey !
Nice resource. I particulary agree with you about #5. Thanks for writing it .

Gama

Comment on 重定向 Bash “time” 命令的输出 by 9rivers

9rivers — Tue, 13 Jul 2010 18:24:31 +0000

OYU，谢谢你的评论！

不过有什么理由认为time是执行在子shell的呢？我认为time还是在当前shell执行，只是它的输出被送到当前shell的自身的标准IO（或者说是上级shell的标准IO）而不是为子进程准备的标准IO。这样当前shell不能捕捉其输出，而父shell总是可以。而command则总是使用当前shell准备好的标准文件描述符。

上面的理解有参考也有我自己的理解，不切实之处欢迎指出。
参考：http://mywiki.wooledge.org/BashFAQ/032

Comment on 重定向 Bash “time” 命令的输出 by 0YU

0YU — Tue, 13 Jul 2010 14:53:22 +0000

我觉得你有个地方说反了(time是subshell,command是当前shell),我上网查了下.应该是:
command是运行在当前shell的,time由于是shell的关键字(which time没有输出)而永远是在subshell进程运行.
这才能解释time command 2> file.txt无效是因为重定向的是当前shell(command)的standard error

Comment on 用VC和gcc同时编译unicode编码的c++源程序 by 9rivers

9rivers — Mon, 14 Jun 2010 07:49:47 +0000

Thanks Tao! Good to know this!

Comment on 用VC和gcc同时编译unicode编码的c++源程序 by Tao Wang

Tao Wang — Mon, 14 Jun 2010 04:41:55 +0000

gcc 4.4以前不支持UTF-8 BOM，但是这个bug: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33415 已经被修复，并且随着gcc 4.4.0发布了，因此，现在的gcc已经可以编译带utf-8 bom的文件了。

Comment on Compile gromacs on Cygwin by 9rivers

9rivers — Fri, 11 Jun 2010 12:33:32 +0000

Hi nbbb,

First, for serial compilation I don’t think there is any difference in functionality than between the binary on Cygwin and LINUX. However, I have seen some posts on internet that some of the MPI libraries do not support Cygwin, e.g. openmpi. In addition, to run a mpi program on Cygwin is a little weird to me. I never tried this.

Talking about the performance I think Cygwin is not a good platform. I prefer MinGW/MSYS or better the native LINUX virtual machine if you’d like to stick to Windows. The reason is Cgywin does not produce ‘native’ WIN32 but POSIX program. The programs compiled on Cygwin need cygwin.dll as an intermediate layer. Therefore, some performance sacrifice must be paid. (see also: http://forums.techarena.in/software-development/1196236.htm )

As my suggestion, you could run your testing on the virtual LINUX machine (e.g. oracle Virtual Box) and then make your final production run on a real LINUX server for the best performance. Or you could compile Gromacs with MinGW or VC++ to make native WIN32 binary and run it on Windows. I didn’t compare the speed of between the Windows version and the LINUX version. But I did compile Gromacs with VC++ successfully. (There is a Windows HPC VS solution of Gromacs on the official website as far as I remember.)

Further discussion is alway welcome!

Ting

Comment on Compile gromacs on Cygwin by nbbb

nbbb — Thu, 10 Jun 2010 16:24:27 +0000

Dear Ting,

I am currently using GROMACS for simulations and I was wondering whether GROMACS on CYGWIN is less capable than GROMACS run on LINUX? i.e. concerning its speed and its ability to simulate larger macromolecules.
I would be very grateful for your help.

Thank you

Comment on Python模块的反安装 by 9rivers

9rivers — Mon, 08 Mar 2010 12:47:47 +0000

对于已安装模块，除了手工删除，我不知道有更好的方法来卸载。所以我觉得Python的包管理有待加强。在PyPI上有一些包管理的项目，例如Setuptools，Distribute等，好像支持反安装，但是我没有用过，所以不知是不是好用。

Comment on Python模块的反安装 by GreatGhoul

GreatGhoul — Mon, 08 Mar 2010 06:05:07 +0000

这倒是个好方法，如果已经安装，又没有trick的模块应该版反安装呢。

Comment on Lammps performance with different compilers by 9rivers

9rivers — Wed, 13 Jan 2010 10:01:54 +0000

Hi, Christopher,
Thanks for the comment!

Please do the test with lammps in parallel mode, which is the way people often use this software.

I’m interested to know your result. Please let me know if you need more information.