How to run FEWZ at LXPLUS


This page is dedicate to give a detailed instruction on how to run FEWZ in lxplus. FEWZ is a generator with NNLO, which is the most feasible higher order calculation for single W, Z boson physics.


(1) install LHAPDF in lxplus :


  • LHAPDF: LHAPDF is a interplator between PDF sets and different generators, which has been widely used in the high energy physics.
  • LHAPDF是一个部分子分布函数(PDF sets)跟不同事例产生子的接口软件,主要是用来把各种PDF引入到产生子中,在高能物理中被广泛使用。

tar xvzf LHAPDF-6.4.0.tar.gz

cd LHAPDF-6.4.0

mkdir ../LHAPDF_640

source /cvmfs/

sh /cvmfs/

./configure --prefix=/afs/

make -j4

make install 

Download PDF sets, take CT14NNLO as example, more PDF sets can be download here.(下载PDF文件,使用CT14NNLO作为例子,更多的PDF文件可以从 这里下载,注意,不需要全部下载,使用那个PDF才下载相应文件)

cd ../LHAPDF_640/share/LHAPDF/


tar xvzf CT14nnlo.tar.gz


tar xvzf CT14lo.tar.gz

<br />

(2) install FEWZ in lxplus


Reminder:please replace "/afs/" to the installed LHAPDF (Step-1)

注意:下面的脚本需要替换/afs/ 成安装好的LHAPDF路径(上一步)


tar xvzf FEWZ_3.1.rc.tar.gz

cd FEWZ_3.1.rc 
  • modify the makefile and create a (修改makefile,并创建
  • create (创建
setenv LHAPDFSYS /afs/

setenv PATH $LHAPDFSYS/bin:${PATH}



setenv PYTHONPATH ${LHAPDFSYS}/lib/python2.7/site-packages:${PYTHONPATH}


source /cvmfs/

sh /cvmfs/ 

  • modify makefile in FEWZ_3.1.rc(修改makefile,在FEWZ_3.1.rc目录下面)

LHADIR = /afs/ 

then comment out the following lines in the makefile, as line 38, 41, 112, 114, 121, 123 - 125.


  • compile, ~ 20 mins (编译,近20分钟)

  • Check bin/ directory, if the complie is succuessful, then you should have both fewzw and fewzz: (检查bin这个目录,需要有fewzw, fewzz两个文件)

(3) local test (本地测试)

cd bin

cp /afs/ .

cp /afs/ .

cp /afs/ .

cp /afs/ .

source ../

./ z Z_LO z8_lo_c14.txt histz.txt txt .. &

<br />

It takes ~ 5 mins to get the results, you could check Z_LO/Z_LO0/ for the results.

In the directory, screen.out is a output for vegas integration, LO.txt is the calculated cross-section results.

Please check "Sigma (pb) = xxx" in the LO.txt, if it is a non-zero number, then, the FEWZ works well.

ps: the vegas integration is used to calculate the cross-section in differnt phase space, and then combine together.



运行结束后,检查LO.txt,如果"Sigma (pb) = xxx" 是一个非0的数字,那么FEWZ是没有问题了。


(4) a quick test in the batch system (在batch系统下面的快速测试)。

Batch system can be used as a computer farm to running paraelle jobs, more details can be found here or there.

(Batch系统可以用来处理大量的并行工作,作为cern的一个计算机节点。更多有用的信息可以在 这里,与 这里找到。)

cp /afs/ .

cp /afs/ .

cp /afs/ . 

modify the according to what you want, (修改一下,根据你的需求)





modify the, change the path of LHAPDFSYS. (修改一下,修改LHAPDFSYS到你自己的LHAPDF的路径)

export LHAPDFSYS=/afs/


It will create a directory named 'qsub' to save the submitting script, and '' is the command to submit all the batch jobs.


You could use bjobs to check the job status. (使用'bjobs'来查看提交工作的状态。)

It takes ~ 5 mins to get the output, as shown in LO_Z_8TeV/LO_Z_8TeV0/, and you will recieve an email to say it is done.


(5) submit jobs for NNLO calculation (提交NNLO计算的jobs)

cp /afs/ .

cp /afs/ . 

modify the according to what you want, (修改一下,根据你的需求)





submit your jobs, for Z boson cross section NNLO calculation, we have 127 sub-jobs.




<br />

After each of sub-jobs is done (> 1 weeks), we can combine results as:(所有子工作结束后,超过一周,合并结果值)

./ Z_8TeV_NNLO NNLO.txt 

(6) Tips: (注意事项)

  • (a) These jobs are CPU time consuming, which may takes ~ 3 - 7 days to finish each sub-job, so be patient. (每个子工作可能需要3-7天来完成,耐心等待。)
  • (b) Mostlikely, the subjobs will be killed due to "CPU usage limit". In that case, you need submit the failed job by hand, as in '' (大部分子工作会由于CPU 使用限制而杀掉,这种情况下,我们重新提交一下这个工作【比如 子工作-22】,具体命令见
bsub -c 100:00 -q 1nw -J fewzz-22 /afs/ 

As mentioned above, the vegas integration is used for FEWZ, which will start from the latest working point, even the job is failed. Like, if the vegas integration stopped at 40 iter, then after you resubmit the job, the FEWZ will begin to calculate the cross section from the 40 iter.


  • (c) When the sub-job failed, it will create file named in the directory, with large size (> 1Gb). So you need to check your CERN email and clear them regularly (per 4 hours), otherwise, your directory will be filled with core.XXX, and the other results cannot write into the disk. (子工作失败后,会产生core.XXX文件,这个文件非常大(>1 Gb),很快就会把你的磁盘填满,所以每隔4小时,最好检查一下CERN邮箱,并清理一下各个子目录。)
rm -rf Z_8TeV_NNLO/Z_8TeV_NNLO*/core.* 
  • (d) For Z boson NNLO calculation, the vegas integration need perform 88 iterations. So please check this when one job is done. The last line of successful job should be something like this (in screen.out): (对于Z玻色子的NNLO计算,需要88步vegas积分,在成功的子工作screen.out最后几行)

So I used the command below to check which job is done (可以用下面的命令来检查那些工作结束了)

grep Thanks Z_8TeV_NNLO/Z_8TeV_NNLO*/screen.out 

combined with bjobs command, we can figure out which job is missing. (与bjobs命令结合起来,可以检查缺少那些文件)

-- HangYin - 2018-06-11

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng FEWZ_submit_test1.PNG r1 manage 6.3 K 2018-06-11 - 11:55 HangYin  
PNGpng FEWZ_submit_test2.PNG r1 manage 27.6 K 2018-06-11 - 11:55 HangYin  
PNGpng FEWZ_submit_test3.PNG r1 manage 150.6 K 2018-06-11 - 12:01 HangYin  
PNGpng FEWZ_submit_test4.PNG r1 manage 19.9 K 2018-06-11 - 14:21 HangYin  
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