MACRO NTUPLE 

* MERGES THE ASCII DATA (hbk/file.txt) INTO A NTUPLE (hbk/file.hbk)

* FILE : ASCII INPUT FILE  ( taken from the shell environment ) 
* HBK  : FILE CONTAINING THE RESULTING NTUPLE
* NEVENT : NUMBER OF EVENTS TO READ, DEFAULT IN PAW IS 1E6

* NTUPLE VARIABLES:
* u,v : surface parameters (eg. angle phi, z-position. See PrimaryGeneratorAction)
* x,y,z:  generated (true) surface point in cartesian coordinates
* px,py,pz: vertex position in cartesian coordinates
* dist:     distance between vertex and intersection
* vx,vy,vz: momentum of particle at vertex
* rx,ry,rz: reconstructed intersection 
* delta :  distance between reconstructed and true intersection
* theta: angle between momentum and surface normal at intersection

FILE   = $ENV(arg1)
HBK    = $ENV(arg2)
NEVENT = $ENV(arg3)
 
*file = hbk/surf.txt
*hbk  = hbk/surf.hbk
*nevent = 100000

MESS PAW: Process [NEVENT] events.

HI/FILE 1 [HBK] 1024 N
NT/CRE 1 'merge' 17 //lun1 ! u v x y z px py pz dist vx vy vz rx ry rz delta theta
NT/READ 1 [FILE] ! ! [NEVENT]

HROUT 0
CLOSE 1