PYTHIA/pythia/pysave.F

   1
   2 C*********************************************************************
   3
   4       SUBROUTINE PYSAVE(ISAVE,IGA)
   5
   6 C...Saves and restores parameter and cross section values for the
   7 C...3 gamma-p and 6 gamma-gamma alnternatives. Also makes random
   8 C...choice between alternatives.
   9       COMMON/PYSUBS/MSEL,MSUB(200),KFIN(2,-40:40),CKIN(200)
  10       COMMON/PYPARS/MSTP(200),PARP(200),MSTI(200),PARI(200)
  11       COMMON/PYINT1/MINT(400),VINT(400)
  12       COMMON/PYINT2/ISET(200),KFPR(200,2),COEF(200,20),ICOL(40,4,2)
  13       COMMON/PYINT5/NGEN(0:200,3),XSEC(0:200,3)
  14       COMMON/PYINT9/DXSEC(0:200)
  15       DOUBLE PRECISION DXSEC
  16       SAVE /PYSUBS/,/PYPARS/,/PYINT1/,/PYINT2/,/PYINT5/,/PYINT9/
  17       DIMENSION NCP(10),NSUBCP(10,20),MSUBCP(10,20),COEFCP(10,20,20),
  18      &NGENCP(10,0:20,3),XSECCP(10,0:20,3),INTCP(10,20),RECP(10,20)
  19       DOUBLE PRECISION DXSECC(10,0:20)
  20       SAVE NCP,NSUBCP,MSUBCP,COEFCP,NGENCP,XSECCP,INTCP,RECP,DXSECC
  21
  22 C...Save list of subprocesses and cross-section information.
  23       IF(ISAVE.EQ.1) THEN
  24         ICP=0
  25         DO 120 I=1,200
  26         IF(MSUB(I).EQ.0.AND.I.NE.96.AND.I.NE.97) GOTO 120
  27         ICP=ICP+1
  28         NSUBCP(IGA,ICP)=I
  29         MSUBCP(IGA,ICP)=MSUB(I)
  30         DO 100 J=1,20
  31         COEFCP(IGA,ICP,J)=COEF(I,J)
  32   100   CONTINUE
  33         DO 110 J=1,3
  34         NGENCP(IGA,ICP,J)=NGEN(I,J)
  35         XSECCP(IGA,ICP,J)=XSEC(I,J)
  36   110   CONTINUE
  37         DXSECC(IGA,ICP)=DXSEC(I)
  38   120   CONTINUE
  39         NCP(IGA)=ICP
  40         DO 130 J=1,3
  41         NGENCP(IGA,0,J)=NGEN(0,J)
  42         XSECCP(IGA,0,J)=XSEC(0,J)
  43   130   CONTINUE
  44         DXSECC(IGA,0)=DXSEC(0)
  45 C...Save various common process variables.
  46         DO 140 J=1,10
  47         INTCP(IGA,J)=MINT(40+J)
  48   140   CONTINUE
  49         INTCP(IGA,11)=MINT(101)
  50         INTCP(IGA,12)=MINT(102)
  51         INTCP(IGA,13)=MINT(107)
  52         INTCP(IGA,14)=MINT(108)
  53         INTCP(IGA,15)=MINT(123)
  54         RECP(IGA,1)=CKIN(3)
  55
  56 C...Save cross-section information only.
  57       ELSEIF(ISAVE.EQ.2) THEN
  58         DO 160 ICP=1,NCP(IGA)
  59         I=NSUBCP(IGA,ICP)
  60         DO 150 J=1,3
  61         NGENCP(IGA,ICP,J)=NGEN(I,J)
  62         XSECCP(IGA,ICP,J)=XSEC(I,J)
  63   150   CONTINUE
  64         DXSECC(IGA,ICP)=DXSEC(I)
  65   160   CONTINUE
  66         DO 170 J=1,3
  67         NGENCP(IGA,0,J)=NGEN(0,J)
  68         XSECCP(IGA,0,J)=XSEC(0,J)
  69   170   CONTINUE
  70         DXSECC(IGA,0)=DXSEC(0)
  71
  72 C...Choose between allowed alternatives.
  73       ELSEIF(ISAVE.EQ.3.OR.ISAVE.EQ.4) THEN
  74         IF(ISAVE.EQ.4) THEN
  75           XSUMCP=0.
  76           DO 180 IG=1,MINT(121)
  77           XSUMCP=XSUMCP+XSECCP(IG,0,1)
  78   180     CONTINUE
  79           XSUMCP=XSUMCP*RLU(0)
  80           DO 190 IG=1,MINT(121)
  81           IGA=IG
  82           XSUMCP=XSUMCP-XSECCP(IG,0,1)
  83           IF(XSUMCP.LE.0.) GOTO 200
  84   190     CONTINUE
  85   200     CONTINUE
  86         ENDIF
  87
  88 C...Restore cross-section information.
  89         DO 210 I=1,200
  90         MSUB(I)=0
  91   210   CONTINUE
  92         DO 240 ICP=1,NCP(IGA)
  93         I=NSUBCP(IGA,ICP)
  94         MSUB(I)=MSUBCP(IGA,ICP)
  95         DO 220 J=1,20
  96         COEF(I,J)=COEFCP(IGA,ICP,J)
  97   220   CONTINUE
  98         DO 230 J=1,3
  99         NGEN(I,J)=NGENCP(IGA,ICP,J)
 100         XSEC(I,J)=XSECCP(IGA,ICP,J)
 101   230   CONTINUE
 102         DXSEC(I)=DXSECC(IGA,ICP)
 103   240   CONTINUE
 104         DO 250 J=1,3
 105         NGEN(0,J)=NGENCP(IGA,0,J)
 106         XSEC(0,J)=XSECCP(IGA,0,J)
 107   250   CONTINUE
 108         DXSEC(0)=DXSECC(IGA,0)
 109
 110 C...Restore various common process variables.
 111         DO 260 J=1,10
 112         MINT(40+J)=INTCP(IGA,J)
 113   260   CONTINUE
 114         MINT(101)=INTCP(IGA,11)
 115         MINT(102)=INTCP(IGA,12)
 116         MINT(107)=INTCP(IGA,13)
 117         MINT(108)=INTCP(IGA,14)
 118         MINT(123)=INTCP(IGA,15)
 119         CKIN(3)=RECP(IGA,1)
 120         CKIN(1)=2.*CKIN(3)
 121
 122 C...Sum up cross-section info (for PYSTAT).
 123       ELSEIF(ISAVE.EQ.5) THEN
 124         DO 270 I=1,200
 125         MSUB(I)=0
 126         NGEN(I,1)=0
 127         NGEN(I,3)=0
 128         XSEC(I,3)=0.
 129   270   CONTINUE
 130         NGEN(0,1)=0
 131         NGEN(0,2)=0
 132         NGEN(0,3)=0
 133         XSEC(0,3)=0
 134         DO 290 IG=1,MINT(121)
 135         DO 280 ICP=1,NCP(IG)
 136         I=NSUBCP(IG,ICP)
 137         IF(MSUBCP(IG,ICP).EQ.1) MSUB(I)=1
 138         NGEN(I,1)=NGEN(I,1)+NGENCP(IG,ICP,1)
 139         NGEN(I,3)=NGEN(I,3)+NGENCP(IG,ICP,3)
 140         XSEC(I,3)=XSEC(I,3)+XSECCP(IG,ICP,3)
 141   280   CONTINUE
 142         NGEN(0,1)=NGEN(0,1)+NGENCP(IG,0,1)
 143         NGEN(0,2)=NGEN(0,2)+NGENCP(IG,0,2)
 144         NGEN(0,3)=NGEN(0,3)+NGENCP(IG,0,3)
 145         XSEC(0,3)=XSEC(0,3)+XSECCP(IG,0,3)
 146   290   CONTINUE
 147       ENDIF
 148
 149       RETURN
 150       END