From wilhelm@ripe.net Tue Sep 14 14:29:38 1999
Date: Mon, 09 Aug 1999 15:38:24 +0200
From: Rene Wilhelm 
To: henk@ripe.net
Subject: ROOT @ginkgo


ROOT Files
==========

... are stored in

   /ncc/ttpro/root_data///

one ROOT file per testbox (like PCKB; all info SND by box) 

example:

	/ncc/ttpro/root_data/1999/08/06/tt16.ripe.net.19990806.root

(the chaining requires files to end in .root)


Starting ROOT
=============

Set environment variables

    ROOTSYS=/usr/local/root
    LD_LIBRARY_PATH=:/usr/local/root/lib

(note the ":" ! )

root binary is in /usr/local/root/bin, you may wish to add that to 
your PATH.

Next copy ~wilhelm/root/.rootrc to your working directory (this makes
it possible to read commands from rootlogon.C upon startup)

To use TT data, you have to load the "delay" library:

    gSystem.Load("/ncc/ttpro/lib/libDelay.so");

Since this has to be done for every TT ROOT session, you probably want
to add this command to your rootlogon.C

To 'attach' files:

    TChain chain("tree");
    chain.Add("/ncc/ttpro/root_data/1999/07/15/tt15.ripe.net.19990715.root");
    chain.Add("/ncc/ttpro/root_data/1999/07/15/tt15.ripe.net.19990716.root");
    ....

(these commands are also good candidates for your rootlogon.C)

And to Draw simple graphs:

    chain.Draw("PacketDelay","TargetId==08 && PacketDelay>0 && PacketDelay<300")

(delays from tt15 to tt08 for *all* chained files; no selection on SourceId,
 since all selected files are from tt15.ripe.net)


For advanced graphs (setting hist options and such), you first have to
create a histogram and fill that with chain.Draw  (also needed when
plotting ArrivalTime; the autoscaling seems to only check first N events
to determine histogram limits)

Example:

    TH1F h1("h1", "time", 1000, 931950000, 933000000)           
    chain.Draw("ArrivalTime>>h1", "ArrivalTime>0")

    TH2F h2("h2", "delay vs time", 1000, 931950000, 933000000, 250, 0, 250)
    chain.Draw("PacketDelay:ArrivalTime>>h2", "TargetId==08") 

	

-- Rene

From wilhelm@ripe.net Tue Sep 14 14:30:12 1999 Date: Thu, 09 Sep 1999 19:59:08 +0200 From: Rene Wilhelm To: johann@ripe.net Cc: fotis@ripe.net, henk@ripe.net Subject: more on ROOT my work with ROOT thusfar is (historically) spread over two directories: /home/wilhelm/ROOT on the 'office' computer cluster /home/wilhelm/root on ginkgo the second one is almost empty, sendpacket.C is result of copy&paste of some interactive tests, createing the plots with measure send/lost packets, or packets which have good/wrong clock stats. the first one is, admittedly, a bit of an undocumented mess. Most usefull are probably: chain.C - the macro used to derive delay parameters (2.5% level, median, 97.5% level) from a chain of root files; this creates a new ROOT file with DelayStats objects. (description of that object in /ncc/ttpro/include/Delay.h) delays.C & stats.C - macros used to create the plots in which we show "long" term trend of delays between TT01 & TT23 (as presented in RIPE32 meeting) maybe this can of help in your work with ROOT. Good luck, -- Rene