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Geant 3 variations: STAR and Alice versions
  Maintenance

This page describes the differences found between the Geant 3.21 codes used in STAR and those in Alice. The former was modified over the years by P.Nevski, the latter by a group of people with many contributions coming from F.Carminati.

The list below is not meant to be exhaustive and should rather be looked at as a general survey. Smaller differences are listed verbarim, whereas significant differences are just stated as such.

There is an important caveat. Function names in the Alice version were changed in the following manner: the leading character "G" was replaced with "G3" everywhere. This makes comparisons a bit harder. There also exist formatting differences.

Directory/Function STAR ALICE
fiface/FLDIST 
IF (IPART.EQ.13.AND.GEKIN.LE.0.02 .OR. IPART.EQ.10) THEN
*       Send low energy neutrons and K0Ls back to GHEISHA
 
fiface/FLUFIN   

(IPART.EQ.8.OR.IPART.EQ.12.OR.IPART.EQ.11.OR.IPART.EQ.23)) THEN
          CALL G3DECAY
* force xi- to decay
fluka vertex.F zeroin.F
fluka/STALIN 
ASTLIN (2,IZ) = MAX (SQRT(ASTLIN(2,IZ)-ASTLIN(1,IZ)**2)

ASTLIN (2,IZ) = MAX (SQRT(MAX(ASTLIN(2,IZ)-ASTLIN(1,IZ)**2,ZERO))
cons/GSMATE   custom calculation of rad and abs lengths
cons   a few occurunces of a custom common block "FIXIT"
matx55
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gbase
=
=
ggeom/GFLRAD 
      DO 60 IS=-1,1,2
         R2=(DX(1)+IS*DZ*XT(1))**2+(DX(2)+IS*DZ*XT(2))**2
         IF(IAXIS.EQ.5) R2=R2+(DX(3)+IS*DZ*XT(3))**2
         R1=SQRT(R2)
         CH=MAX(CH,R1+R)
         CL=MIN(CL,R1-R)
   60 CONTINUE


      IF(IAXIS.EQ.4) ST2=(1+XT(3))*(1-XT(3))
      DR=SQRT(DZ*DZ*ST2+R*R)
      CL=DXS-DR
      IF(CL.LT.0.0) CL=0.0
      CH=DXS+DR
gphys/GBREME   
 IF(ABS(AL).GT.1.e-6) THEN
gphys/GFLUCT   
 DE=DE2(FPOT,RNDM(1))
geocad/GCTSET 
 DIMENSION PAR(50) 
 DIMENSION PAR(100)
gheisha/CASK0B 
    62 IPA(1)=14  ! Invert order of statements to avoid g77 bug
       IPA(2)=13  ! (do not change physics, even if its wrong)

    62 IPA(1)=13
       IPA(2)=14
gheisha/CASPIP 
       DATA SUPP/0.,0.2,0.45,0.55,0.65,0.75,0.85,0.90,0.94,0.98/
       DATA CECH/0.33,0.27,0.29,0.31,0.27,0.18,0.13,0.10,0.09,0.07/

       DATA SUPP/0.,0.4,0.55,0.65,0.75,0.82,0.86,0.90,0.94,0.98/
       DATA CECH/1.0,0.95,0.79,0.32,0.19,0.16,0.14,0.12,0.1,0.08/
gheisha/CASPIP Differrences in calculation of the pion cross section
-"-
gheisha/GENXPT Numerous arithmetic differences Correction for the rndm boundary problem
gheisha/TWOB Numerous arithmetic differences Gheisha corrections suggested by Gary Bower
gheisha/TWOCLU Numerous arithmetic differences Correction for the rndm boundary problemr
gscan
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Last updated by Maxim Potekhin on 05/14/2004