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Astrophysics

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Support to Users of Astrophysics

Currently the group of people running on the Grid infrastructure is made of the following people

  • Andres Curto
  • Enrique Martinez
  • Jose Maria Diego
  • Patricio Vielva
  • Marcos Cruz
  • Carlos Monteserin
  • Daniel Herranz


If you are a member of the astrophysics group and want to join the group have a look at this [General Support Documentation] first, and then contact Isabel Campos.


Submission of Serial Batch Jobs

In what follows we will describe the submission of serial batch jobs to the Grid resources at IFCA whatever the project is. The example contains a restriction line which forces the job to end up on our machines locally, both at the level of CPU and at the level of Storage.

Advanced users can try to remove this restriction and go the Grid.

  • Simple Job without Storage Elements (transferred data under 20 MB)

To submit a serial job to the grid batch queues of IFCA the job has to be described in the language of the Grid batch system, this is called Job Description Language (JDL). This is an example:

 # Mandatory attributes
 Executable = "myexe";
 StdOutput = "myexe.out";
 StdError = "myexe.err";
 # I/O files to be staged from/to the User Interface
 InputSandbox = {"myexe","input.dat"};
 OutputSandbox = {"myexe.out","myexe.err","myoutput.dat"};
 Requirements= other.GlueCEUniqueID == "i2gce01.ifca.es:2119/jobmanager-lcgpbs-iplanck";


This is the description of the job:

1. Executes the binary myexe with needs the file input.dat to work.

2. Writes the STDOUT and STDERR in myexe.out and myexe.err

3. The output of the program is myoutput.dat

The size of data which can be carried on SandBoxes is limited to a few Mbytes. Evidently there are few real scientific applications that can work on such basic premises. However we strongly suggest users to try and succeed dummy tests like this before getting to more complicated scenarios.


  • Using the Storage Elements for massive Input/Output

In most real applications one needs to deal with data sizes that do not fit in the SandBox limitation. The way to proceed is then based on three steps

 1. Store in the Grid in the apropriate place the Input data our program needs to run

Every VO, in particular iplanck has a dedicated directory for storage under /grid In order to access that directory first export the variable LFC_HOST to be at the central host for file catalogs of inteugrid, and then use the following commands

 [isabel@i2gui01 i2g-test]$ export LFC_HOST=lfc01.lip.pt
 [isabel@i2gui01 i2g-test]$ lfc-ls /grid/iplanck
 isabel
 rmarco
 curto

Create a directory to store input and protect it acording to your needs. For example, you might consider to stored all your maps in a directory like CMB_MAPS and let read access to every iplanck member

 [isabel@i2gui01 i2g-test]$ lfc-mkdir /grid/iplanck/CMB_MAPS
 [isabel@i2gui01 i2g-test]$ lfc-chmod 744 /grid/iplanck/dummy
 [isabel@i2gui01 i2g-test]$ lfc-ls -l /grid/iplanck/
 drwxr--r--   0 102      106                       0 Feb 15 16:15 CMB_MAPS


Now let us copy a big data file from your home directory in the User Interface to this directory

 lcg-cr --vo iplanck -l lfn:/grid/iplanck/isabel/mytarball.tar file:///home/isabel/mytarball.tar

the file mytarball.tar will be accesible for Jobs running on the grid when referencing it as lfn:/grid/iplanck/isabel/mytarball.tar

 2. Design a shell script that used inside a JDL script makes the input available to
 the job, and puts the output available on a Storage Element once the Job has completed.

This in principle implies to copy the files we need before the job executes from a Storage Element to the actual node that is carrying the calculation. When the job completes, one option is to tar/gzip the result and copy it to a Storage Element. This is an example script which would do the job

 cat my-script.sh
 #!/bin/sh
 # Debug info
 echo \| Execution start: `date` \| Host: `hostname` \| User: `whoami` \| Path: `pwd` \|
 #Let us first get the input of the simulation in place
 lcg-cp --vo iplanck lfn:/grid/iplanck/CMB_MAPS/map.tar.gz file:///tmp/map.tar.gz
 #Let us create a directory there (it is not mandatory!)  
 mkdir RUN_febrero15
 cp /tmp/map.tar.gz RUN_febrero15/.
 cp executable RUN_febrero15/.
 cd RUN_febrero15/
 tar xzvf map.tar.gz
 rm map.tar.gz
 ./executable 
 #Once here the program has ended, we tar the result and put it on an accesible place
 cd $HOME
 tar czvf run_febrero15.tgz RUN_febrero15/*
 lcg-cr --vo iplanck -l lfn:/grid/iplanck/isabel/run_febrero_15.tgz file://$HOME/run_febrero15.tgz
 # Debug info
 echo \| Execution end: `date` \|


The result is now accesible from the User Interface where the user is logged, and can be retrieve by the command lcg-cp

 lcg-cp --vo iplanck lfn:/grid/iplanck/isabel/run_febrero15.tgz file://$HOME/gridruns/run_febrero15.tgz


Finally, this would be the JDL description of this job. Notice we have replaced the executable by the name of the script, my-script.sh

 # Mandatory attributes
 Executable = "my-script.sh";
 StdOutput = "my-script.out";
 StdError = "my-script.err";
 # Environment variables
 Environment = {"LFC_HOST=lfc01.lip.pt"};
 # I/O files to be staged from/to the User Interface
 InputSandbox = {"my-script.sh","executable"};
 OutputSandbox = {"my-script.out","my-script.err"};
 Requirements= other.GlueCEUniqueID == "i2gce01.ifca.es:2119/jobmanager-lcgpbs-ifusion";


The command edg-job-submit will submit this job to the IFCA resources and use our File Catalog as reference for file stanging.


Submitting long jobs

An important point to consider is that the proxy of the user that has submitted the job has to be valid all the period that the job is supossed to queue and to run.

The initialization of the proxy is made by default for 12 hours. It is possible though to initialize the proxy for a longer period.

However the elegant solution to avoid that the job dies because the user proxy has expired is to use the mechanism of automatic job renovation by a proxy server. In order to use this facility one has to add to do the following

  #Create and Store a long term proxy on the proxy server
  [isabel@i2gui01 i2g-test]$ myproxy-init -s i2gpx01.ifca.es -d -n
  Your identity: /C=ES/O=DATAGRID-ES/O=BIFI/CN=Isabel Campos Plasencia
  Enter GRID pass phrase for this identity:
  Creating proxy .......................................... Done 
  Proxy Verify OK
  Your proxy is valid until: Thu Feb 22 17:12:25 2007
  A proxy valid for 168 hours (7.0 days) for user /C=ES/O=DATAGRID-ES/O=BIFI/CN=Isabel Campos Plasencia now    exists on i2gpx01.ifca.es.

The commanda myproxy-init has created a one-week valid proxy on the IFCA proxy server, i2gpx.ifca.es Next the user has to a line in the JDL job description informing the job about the location of the proxy

  MyProxyServer=i2gpx.ifca.es

Once the job is done, destroy that long proxy, because in general it is not safe to have long proxies impersonating us over the network.

  [isabel@i2gui01 i2g-test]$ myproxy-destroy -s i2gpx01.ifca.es -d
  Default MyProxy credential for user /C=ES/O=DATAGRID-ES/O=BIFI/CN=Isabel Campos Plasencia was successfully   removed.

Submission of Parallel MPI Batch Jobs

Dealing with Storage Elements

Currently the following Storage Elements are available to the iplanck Virtual Organization

  [isabel@i2gui01 AstroFisica]$ lcg-infosites --vo iplanck se
  Avail Space(Kb) Used Space(Kb)  Type    SEs
  ----------------------------------------------------------
  105471484       4780676         n.a     se-ieg.bifi.unizar.es
  193471324       923487          n.a     se.i2g.cesga.es
  30540000000     7440000000      n.a     dpm.cyf-kr.edu.pl
  1131455168      122804          n.a     i2gse01.ifca.es
  1926285861      6972            n.a     dcache01.lip.pt
  72982596        32840           n.a     i2g-se01.lip.pt


By default the Storage Element employed is the one at IFCA. A different one can be specified using the flag '-d

 lcg-cr --vo iplanck -d se.i2g.cesga.es -l lfn:/grid/iplanck/isabel/testing  file:///home/isabel/FH/FeynHiggs

Using HealPix Software

We have installed in the int.eu.grid testbed the version 2.01 of Healpix. Here follows and example of how to use the program synfast to execute analysis jobs of .fits files.

We will run on the grid the following analysis using synfast:

 simul_type = 1
 nsmax = 2048
 nlmax = 1500 
 infile = cmb_85862536.fits
 iseed = 0
 fwhm_arcmin = 5
 beam_file = 
 almsfile = 
 plmfile = 
 outfile = cmb_8.fits
 outfile_alms = 
      SYNFAST> Generating random number seed
      SYNFAST> Generating alm coefficients
      SYNFAST> Pixel window file:/home/isabel/Healpix_2.01/data/pixel_window_n2048.fits
      >>>>> keyword TEMPTYPE not found <<<<<
      Will assume THERMO
      Generating gaussian beam of FHWM [arcmin] =    5.00000000000000
      SYNFAST> Generating sky map(s)
      SYNFAST> Writing sky map to FITS file
     Report Card for SYNFAST simulation run
     ----------------------------------------
     Temperature alone
  Input power spectrum : cmb_85862536.fits
  Multipole range      : 0 < l <=     1500
  Number of pixels     :         50331648
  Pixel size in arcmin :           1.7177
  Initial random # seed:        170503069
  Gauss. FWHM in arcmin:           5.0000
  Output map           : cmb_8.fits
  Clock and CPU time [s] :      159.10     106.52
  SYNFAST> normal completion


  • First we need to pack together the files needed for the run. These are first the .fits file
 fits file: cmb_85862536.fits

The file profile.HEALPix to set the environemnt variable for the run

 cat profile.HEALPix
 HEALPIX=$VO_IPLANCK_SW_DIR/Healpix_2.01
 HEXE=$VO_IPLANCK_SW_DIR/Healpix_2.01/bin
 PATH="${PATH}:${HEXE}"
 export HEALPIX HEXE PATH
 alias hidl="idl $VO_IPLANCK_SW_DIR/Healpix_2.01/src/idl/HEALPix_startup"
 alias hidlde="idlde $VO_IPLANCK_SW_DIR/Healpix_2.01/src/idl/HEALPix_startup"

The directory $VO_IPLANCK_SW_DIR is a directory where only the software manager can access, and where the software of general interest should be installed (contact Isabel if you need something here).

Next we need the parameters file describing the input to synfast. In this way we will run synfast --single parameters.txt

 isabel@i2gui01> more parameters.txt
 simul_type = 1
 nsmax = 2048
 nlmax = 1500
 infile = cmb_85862536.fits
 iseed = 0
 fwhm_arcmin = 5
 beam_file = 
 almsfile = 
 plmfile = 
 outfile = !cmb_8.fits
 outfile_alms = 


We pack everything

 tar czvf healpix.tgz cmb_85862536.fits parameters.txt profile.HEALPix 

This is the JDL description of the Job:

 # Mandatory attributes
 Executable = "healpix.sh";
 StdOutput = "healpix.out";
 StdError = "healpix.err";
 # I/O files to be staged from/to the User Interface
 InputSandbox = {"healpix.sh","healpix.tgz"};
 OutputSandbox = {"healpix.out","healpix.err","cmb_8.gif"};

This is the actual scrip healpix.sh where the is described. We also use map2gif to produce the gif image and send it back in the OutputSandbox. The results is too large to fit in a Sandbox and is copied to an storage element in the usual way:

 isabel@i2gui01> more healpix.sh
 #!/bin/sh
 # Debug info
 echo \| Execution start: `date` \| Host: `hostname` \| User: `whoami` \| Path: `pwd` \|
 echo $VO_IPLANCK_SW_DIR
 # Program execution
 tar xzvf healpix.tgz
 # Source the environment of HealPix
 . profile.HEALPix
 synfast --single script.sh
 map2gif -inp cmb_8.fits -out cmb_8.gif
 tar czvf cmb_8fits.tgz cmb_8.fits
 lcg-cr -v --vo iplanck -d se.i2g.cesga.es -l lfn:/grid/iplanck/isabel/cmb_8fits.tgz file://cmb_8fits.tgz
 #Delete files after running 
 rm cmb_8.fits cmb_8fits.tgz
 # Debug info
 echo \| Execution end: `date` \|
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