Installation instructions for fastjet
-------------------------------------

As a first step the user should decide whether or not they want to
have access to the N ln N algorithms for the kt algorithm, based on
the Computational Geometry Algorithms Library (CGAL).

If the user does not wish to use it, he or she should ensure that the
Makefile in the top directory has the line

USE_CGAL = no

Otherwise it should read

USE_CGAL = yes

In that case the user should first download CGAL from
http://www.cgal.org/ and then compile and install it. Under linux, she
or he will have to ensure that an environment variable CGAL_MAKEFILE
points to the Makefile generated by CGAL at install time, containing
various definitions of locations of include files. CGAL will encourage
the user to set this variable during the install process.

Then in the src/ directory do

  make
  make install

which places the fastjet library in lib/. 

To run the example program cd to the example directory and do

  make fastjet_example
  ./fastjet_example < data/single-event.dat

The output should be 

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
#---------------------------------------------------------------------
#                      FastJet release 2.0                       
#            Written by Matteo Cacciari and Gavin Salam          
#            http://www.lpthe.jussieu.fr/~salam/fastjet          
#                                                                        
# Longitudinally invariant Kt Jet clustering, using the fast geometric
# algorithms of hep-ph/0512210 (please cite this if you use FastJet)  
# This package makes use of the CGAL library: http://www.cgal.org/    
# This package incorporates T.Chan's closest-pair algorithm, Proc. 13th     
# ACM-SIAM Symposium on Discrete Algorithms, pp.472-473, 2002
#---------------------------------------------------------------------
Strategy adopted by FastJet was N2Tiled

Printing inclusive jets with pt > 5 GeV
---------------------------------------
jet #        rapidity             phi              pt  n constituents
    0     -0.86730713      2.90511470    983.38727662       35
    1      0.22380471      6.04226446    910.28808604       52
    2     -1.16520657      6.04589034     70.78886044       48
    3     -2.34731970      1.25431317     10.72317440       18
    4     -1.19479918      0.80734483      8.29342805       15
    5     -1.71897064      4.01955399      8.16413672        9
    6     -4.71909257      4.09173629      5.57326514       15
    7      3.42713139      5.74362063      5.17254118       13
    8     -4.83615264      2.20502275      5.02711586       12

Printing exclusive jets with dcut = 25 GeV^2
--------------------------------------------
jet #        rapidity             phi              pt  n constituents
    0     -0.86730713      2.90511470    983.38727662       35
    1      0.22093749      6.02911715    898.62586887       29
    2     -1.16520657      6.04589034     70.78886044       48
    3      0.36257181      0.54763129     16.65531147       23
    4     -2.34731970      1.25431317     10.72317440       18
    5     -1.19479918      0.80734483      8.29342805       15
    6     -1.71897064      4.01955399      8.16413672        9
    7     -4.71909257      4.09173629      5.57326514       15
    8      3.42713139      5.74362063      5.17254118       13
    9     -4.83615264      2.20502275      5.02711586       12
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Additionally the example/ directory contains the following other
programs

ktjet_example		
	same example program, but written with ktjet, to illustrate
	similarities and differences with fastjet_example. For
	compilation to work please set the KTJET_INCLUDE and
	KTJET_LIBRARY variables in the fastjet main Makefile.

fastjet_timing
ktjet_timing
	programs for testing output and timings of the two programs --
	may be run with a variety of command-line options to control
	behaviour -- see the beginning of fastjet_timing.cc for
	further information.

fastjet_areas
	example program for evaluating the areas of the jets in 
	a single event (it reads in the same input file as fastjet_example)

fastjet_subtraction
	example program which uses the areas calculated by FastJet
	for each jet to perform the subtraction of the background generated
	by a number of pileup events. Sample input files for production
	at high luminosity at the LHC of a Z boson, an hypotetical Z', 
	or a dijet event with a ptmin = 100 GeV are in example/data/
 
fastjet_example_v1_interface.cc
        same as fastjet_example, but using the (now deprecated) interface
	of FastJet v1.0. It still compiles correctly with v2.0, backward
	compatibility having been ensured.
