ISAJET/code/logyth.F

   1 #include "isajet/pilot.h"
   2       LOGICAL FUNCTION LOGYTH(IERR)
   3 C
   4 C       SET AND CHECK LIMITS FOR JET Y AND THETA
   5 C
   6 #include "isajet/itapes.inc"
   7 #include "isajet/jetlim.inc"
   8 #include "isajet/primar.inc"
   9 #include "isajet/jetpar.inc"
  10 #include "isajet/const.inc"
  11 #include "isajet/dylim.inc"
  12 #include "isajet/keys.inc"
  13 #include "isajet/q1q2.inc"
  14       DATA UNDEF/-.9E9/
  15 C
  16 C            INVERSE HYPERBOLIC COSINE FUNCTION
  17       ACOSH(X)=ALOG(X+SQRT(X**2-1.0))
  18 C            INVERSE HYPERBOLIC SINE FUNCTION
  19       ASINH(X)=ALOG(X+SQRT(X**2+1.0))
  20 C
  21       HALFPI=PI/2.
  22       LOGYTH=.TRUE.
  23 C
  24       DO 30 I=1,NJET
  25       FIXYJ(I)=.FALSE.
  26 C
  27       IF(FIXP(I).AND.FIXPT(I)) THEN
  28         STH(I)=PT(I)/P(I)
  29         CTHS(1,I)=SQRT(1.-STH(I)**2)
  30         CTHS(2,I)=-CTHS(1,I)
  31         THS(1,I)=ATAN2(STH(I),CTHS(1,I))
  32         THS(2,I)=ATAN2(STH(I),CTHS(2,I))
  33         YJS(1,I)=-ALOG(TAN(THS(1,I)/2.))
  34         YJS(2,I)=-ALOG(TAN(THS(2,I)/2.))
  35         XJS(1,I)=P(I)*CTHS(1,I)/HALFE
  36         XJS(2,I)=P(I)*CTHS(2,I)/HALFE
  37         YJMAX(I)=YJS(2,I)
  38         THMAX(I)=THS(1,I)
  39         THMIN(I)=THS(2,I)
  40         IF(YJMIN(I).EQ.YJMAX(I)) FIXYJ(I)=.TRUE.
  41       ENDIF
  42 C
  43 C
  44       IF(YJMIN(I).LT.UNDEF.AND.YJMAX(I).LT.UNDEF) THEN
  45 C
  46         IF(THMIN(I).LT.UNDEF.AND.THMAX(I).LT.UNDEF) THEN
  47           YJMAX(I)=ACOSH(HALFE/PTMIN(I))
  48           YJMIN(I)=-YJMAX(I)
  49           THMIN(I)=2.*ATAN(EXP(-YJMAX(I)))
  50           THMAX(I)=2.*ATAN(EXP(-YJMIN(I)))
  51         ENDIF
  52 C
  53         IF(THMAX(I).LT.UNDEF) FIXYJ(I)=.TRUE.
  54         IF(THMIN(I).LT.UNDEF) THMIN(I)=.001
  55         IF(FIXYJ(I)) THMAX(I)=THMIN(I)
  56         YJMIN(I)=-ALOG(TAN(THMAX(I)/2.))
  57         YJMAX(I)=-ALOG(TAN(THMIN(I)/2.))
  58         THMIN(I)=2.*ATAN(EXP(-YJMAX(I)))
  59         THMAX(I)=2.*ATAN(EXP(-YJMIN(I)))
  60       ENDIF
  61 C
  62 C
  63       IF(YJMAX(I).LT.UNDEF) FIXYJ(I)=.TRUE.
  64       IF(YJMIN(I).LT.UNDEF) YJMIN(I)=-YJMAX(I)
  65       IF(FIXYJ(I)) YJMAX(I)=YJMIN(I)
  66       THMIN(I)=2.*ATAN(EXP(-YJMAX(I)))
  67       THMAX(I)=2.*ATAN(EXP(-YJMIN(I)))
  68 C
  69       IF(FIXYJ(I)) THEN
  70         YJ(I)=YJMIN(I)
  71         TH(I)=THMIN(I)
  72         STH(I)=SIN(TH(I))
  73         CTH(I)=COS(TH(I))
  74         IF(FIXPT(I)) P(I)=PT(I)/STH(I)
  75         IF(FIXP(I)) PT(I)=P(I)*STH(I)
  76 C
  77         IF((FIXP(I).OR.FIXPT(I))) THEN
  78           XJ(I)=P(I)*CTH(I)/HALFE
  79           XJMIN(I)=XJ(I)
  80           XJMAX(I)=XJ(I)
  81         ENDIF
  82 C
  83       ENDIF
  84 C
  85 C          CHECK PT LIMITS WITH P AND THETA LIMITS
  86       IF(.NOT.FIXPT(I)) THEN
  87         THETA1=AMIN1(THMIN(I),PI-THMAX(I))
  88         THETA2=HALFPI
  89         IF(THMAX(I).LT.HALFPI) THETA2=THMAX(I)
  90         IF(THMIN(I).GT.HALFPI) THETA2=THMIN(I)
  91         PT1=PMIN(I)*SIN(THETA1)
  92         PTMIN(I)=AMAX1(PTMIN(I),PT1)
  93         PT2=PMAX(I)*SIN(THETA2)
  94         PTMAX(I)=AMIN1(PTMAX(I),PT2)
  95       ENDIF
  96 C
  97    30 CONTINUE
  98 C
  99       RETURN
 100       END