Change of argument list of methods GetPadCxy, GetPadIxy, SetHit and FirstPad

[u/mrichter/AliRoot.git] / PYTHIA / jetset / lu3ent.F

 
C********************************************************************* 
 
      SUBROUTINE LU3ENT(IP,KF1,KF2,KF3,PECM,X1,X3) 
 
C...Purpose: to store three partons or particles in their CM frame, 
C...with the first along the +z axis and the third in the (x,z) 
C...plane with x > 0. 
      COMMON/LUJETS/N,K(4000,5),P(4000,5),V(4000,5) 
      COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200) 
      COMMON/LUDAT2/KCHG(500,3),PMAS(500,4),PARF(2000),VCKM(4,4) 
      SAVE /LUJETS/,/LUDAT1/,/LUDAT2/ 
 
C...Standard checks. 
      MSTU(28)=0 
      IF(MSTU(12).GE.1) CALL LULIST(0) 
      IPA=MAX(1,IABS(IP)) 
      IF(IPA.GT.MSTU(4)-2) CALL LUERRM(21, 
     &'(LU3ENT:) writing outside LUJETS memory') 
      KC1=LUCOMP(KF1) 
      KC2=LUCOMP(KF2) 
      KC3=LUCOMP(KF3) 
      IF(KC1.EQ.0.OR.KC2.EQ.0.OR.KC3.EQ.0) CALL LUERRM(12, 
     &'(LU3ENT:) unknown flavour code') 
 
C...Find masses. Reset K, P and V vectors. 
      PM1=0. 
      IF(MSTU(10).EQ.1) PM1=P(IPA,5) 
      IF(MSTU(10).GE.2) PM1=ULMASS(KF1) 
      PM2=0. 
      IF(MSTU(10).EQ.1) PM2=P(IPA+1,5) 
      IF(MSTU(10).GE.2) PM2=ULMASS(KF2) 
      PM3=0. 
      IF(MSTU(10).EQ.1) PM3=P(IPA+2,5) 
      IF(MSTU(10).GE.2) PM3=ULMASS(KF3) 
      DO 110 I=IPA,IPA+2 
      DO 100 J=1,5 
      K(I,J)=0 
      P(I,J)=0. 
      V(I,J)=0. 
  100 CONTINUE 
  110 CONTINUE 
 
C...Check flavours. 
      KQ1=KCHG(KC1,2)*ISIGN(1,KF1) 
      KQ2=KCHG(KC2,2)*ISIGN(1,KF2) 
      KQ3=KCHG(KC3,2)*ISIGN(1,KF3) 
      IF(MSTU(19).EQ.1) THEN 
        MSTU(19)=0 
      ELSEIF(KQ1.EQ.0.AND.KQ2.EQ.0.AND.KQ3.EQ.0) THEN 
      ELSEIF(KQ1.NE.0.AND.KQ2.EQ.2.AND.(KQ1+KQ3.EQ.0.OR. 
     &KQ1+KQ3.EQ.4)) THEN 
      ELSE 
        CALL LUERRM(2,'(LU3ENT:) unphysical flavour combination') 
      ENDIF 
      K(IPA,2)=KF1 
      K(IPA+1,2)=KF2 
      K(IPA+2,2)=KF3 
 
C...Store partons/particles in K vectors for normal case. 
      IF(IP.GE.0) THEN 
        K(IPA,1)=1 
        IF(KQ1.NE.0.AND.(KQ2.NE.0.OR.KQ3.NE.0)) K(IPA,1)=2 
        K(IPA+1,1)=1 
        IF(KQ2.NE.0.AND.KQ3.NE.0) K(IPA+1,1)=2 
        K(IPA+2,1)=1 
 
C...Store partons in K vectors for parton shower evolution. 
      ELSE 
        K(IPA,1)=3 
        K(IPA+1,1)=3 
        K(IPA+2,1)=3 
        KCS=4 
        IF(KQ1.EQ.-1) KCS=5 
        K(IPA,KCS)=MSTU(5)*(IPA+1) 
        K(IPA,9-KCS)=MSTU(5)*(IPA+2) 
        K(IPA+1,KCS)=MSTU(5)*(IPA+2) 
        K(IPA+1,9-KCS)=MSTU(5)*IPA 
        K(IPA+2,KCS)=MSTU(5)*IPA 
        K(IPA+2,9-KCS)=MSTU(5)*(IPA+1) 
      ENDIF 
 
C...Check kinematics. 
      MKERR=0 
      IF(0.5*X1*PECM.LE.PM1.OR.0.5*(2.-X1-X3)*PECM.LE.PM2.OR. 
     &0.5*X3*PECM.LE.PM3) MKERR=1 
      PA1=SQRT(MAX(1E-10,(0.5*X1*PECM)**2-PM1**2)) 
      PA2=SQRT(MAX(1E-10,(0.5*(2.-X1-X3)*PECM)**2-PM2**2)) 
      PA3=SQRT(MAX(1E-10,(0.5*X3*PECM)**2-PM3**2)) 
      CTHE2=(PA3**2-PA1**2-PA2**2)/(2.*PA1*PA2) 
      CTHE3=(PA2**2-PA1**2-PA3**2)/(2.*PA1*PA3) 
      IF(ABS(CTHE2).GE.1.001.OR.ABS(CTHE3).GE.1.001) MKERR=1 
      CTHE3=MAX(-1.,MIN(1.,CTHE3)) 
      IF(MKERR.NE.0) CALL LUERRM(13, 
     &'(LU3ENT:) unphysical kinematical variable setup') 
 
C...Store partons/particles in P vectors. 
      P(IPA,3)=PA1 
      P(IPA,4)=SQRT(PA1**2+PM1**2) 
      P(IPA,5)=PM1 
      P(IPA+2,1)=PA3*SQRT(1.-CTHE3**2) 
      P(IPA+2,3)=PA3*CTHE3 
      P(IPA+2,4)=SQRT(PA3**2+PM3**2) 
      P(IPA+2,5)=PM3 
      P(IPA+1,1)=-P(IPA+2,1) 
      P(IPA+1,3)=-P(IPA,3)-P(IPA+2,3) 
      P(IPA+1,4)=SQRT(P(IPA+1,1)**2+P(IPA+1,3)**2+PM2**2) 
      P(IPA+1,5)=PM2 
 
C...Set N. Optionally fragment/decay. 
      N=IPA+2 
      IF(IP.EQ.0) CALL LUEXEC 
 
      RETURN 
      END