[u/mrichter/AliRoot.git] / HERWIG / src / hwubst.f


CDECK  ID>, HWUBST.

*CMZ :-        -18/10/93  10.21.56  by  Mike Seymour

*-- Author :    Mike Seymour

C-----------------------------------------------------------------------

      SUBROUTINE HWUBST(IOPT)

C-----------------------------------------------------------------------

C     BOOST THE ENTIRE EVENT RECORD TO (IOPT=1) OR FROM (IOPT=0) ITS

C     CENTRE-OF-MASS FRAME, WITH INCOMING HADRONS ON Z-AXIS

C-----------------------------------------------------------------------

      INCLUDE 'HERWIG61.INC'

      DOUBLE PRECISION PBOOST(5),RBOOST(3,3)

      INTEGER IOPT,IHEP,BOOSTD,IHAD

      SAVE BOOSTD,PBOOST,RBOOST

      DATA BOOSTD/-1/

      IF (IERROR.NE.0) RETURN

      IF (IOPT.EQ.1) THEN

C---FIND FIRST INCOMING HADRON

        IHAD=1

        IF (JDAHEP(1,IHAD).NE.0) IHAD=JDAHEP(1,IHAD)

C---IF WE'RE ALREADY IN THE RIGHT FRAME, DON'T DO ANYTHING

        IF (PHEP(1,3)**2+PHEP(2,3)**2+PHEP(3,3)**2.EQ.ZERO .AND.

     &      PHEP(1,IHAD)**2+PHEP(2,IHAD)**2.EQ.ZERO) RETURN

C---FIND AND APPLY BOOST

        CALL HWVEQU(5,PHEP(1,3),PBOOST)

        DO 100 IHEP=1,NHEP

          CALL HWULOF(PBOOST,PHEP(1,IHEP),PHEP(1,IHEP))

          CALL HWULOF(PBOOST,VHEP(1,IHEP),VHEP(1,IHEP))

 100    CONTINUE

        CALL HWULOF(PBOOST,VTXPIP,VTXPIP)

C---FIND AND APPLY ROTATION TO PUT IT ON Z-AXIS

        CALL HWUROT(PHEP(1,IHAD),ONE,ZERO,RBOOST)

        DO 110 IHEP=1,NHEP

          CALL HWUROF(RBOOST,PHEP(1,IHEP),PHEP(1,IHEP))

          CALL HWUROF(RBOOST,VHEP(1,IHEP),VHEP(1,IHEP))

 110    CONTINUE

        CALL HWUROF(RBOOST,VTXPIP,VTXPIP)

C---ENSURE THAT WE ONLY EVER UNBOOST THE SAME EVENT THAT WE BOOSTED

C   (BEARING IN MIND THAT NWGTS IS UPDATED AFTER GENERATING THE WEIGHT)

        BOOSTD=NWGTS+1

      ELSEIF (IOPT.EQ.0) THEN

        IF (BOOSTD.NE.NWGTS) RETURN

C---UNDO ROTATION AND BOOST

        DO 200 IHEP=1,NHEP

          CALL HWUROB(RBOOST,PHEP(1,IHEP),PHEP(1,IHEP))

          CALL HWULOB(PBOOST,PHEP(1,IHEP),PHEP(1,IHEP))

          CALL HWUROB(RBOOST,VHEP(1,IHEP),VHEP(1,IHEP))

          CALL HWULB4(PBOOST,VHEP(1,IHEP),VHEP(1,IHEP))

 200    CONTINUE

      ENDIF

      END
Commit	Line	Data
3820ca8e	1
	2	CDECK ID>, HWUBST.
	3
	4	*CMZ :- -18/10/93 10.21.56 by Mike Seymour
	5
	6	*-- Author : Mike Seymour
	7
	8	C-----------------------------------------------------------------------
	9
	10	SUBROUTINE HWUBST(IOPT)
	11
	12	C-----------------------------------------------------------------------
	13
	14	C BOOST THE ENTIRE EVENT RECORD TO (IOPT=1) OR FROM (IOPT=0) ITS
	15
	16	C CENTRE-OF-MASS FRAME, WITH INCOMING HADRONS ON Z-AXIS
	17
	18	C-----------------------------------------------------------------------
	19
	20	INCLUDE 'HERWIG61.INC'
	21
	22	DOUBLE PRECISION PBOOST(5),RBOOST(3,3)
	23
	24	INTEGER IOPT,IHEP,BOOSTD,IHAD
	25
	26	SAVE BOOSTD,PBOOST,RBOOST
	27
	28	DATA BOOSTD/-1/
	29
	30	IF (IERROR.NE.0) RETURN
	31
	32	IF (IOPT.EQ.1) THEN
	33
	34	C---FIND FIRST INCOMING HADRON
	35
	36	IHAD=1
	37
	38	IF (JDAHEP(1,IHAD).NE.0) IHAD=JDAHEP(1,IHAD)
	39
	40	C---IF WE'RE ALREADY IN THE RIGHT FRAME, DON'T DO ANYTHING
	41
	42	IF (PHEP(1,3)2+PHEP(2,3)2+PHEP(3,3)**2.EQ.ZERO .AND.
	43
	44	& PHEP(1,IHAD)2+PHEP(2,IHAD)2.EQ.ZERO) RETURN
	45
	46	C---FIND AND APPLY BOOST
	47
	48	CALL HWVEQU(5,PHEP(1,3),PBOOST)
	49
	50	DO 100 IHEP=1,NHEP
	51
	52	CALL HWULOF(PBOOST,PHEP(1,IHEP),PHEP(1,IHEP))
	53
	54	CALL HWULOF(PBOOST,VHEP(1,IHEP),VHEP(1,IHEP))
	55
	56	100 CONTINUE
	57
	58	CALL HWULOF(PBOOST,VTXPIP,VTXPIP)
	59
	60	C---FIND AND APPLY ROTATION TO PUT IT ON Z-AXIS
	61
	62	CALL HWUROT(PHEP(1,IHAD),ONE,ZERO,RBOOST)
	63
	64	DO 110 IHEP=1,NHEP
65
66	CALL HWUROF(RBOOST,PHEP(1,IHEP),PHEP(1,IHEP))
67
68	CALL HWUROF(RBOOST,VHEP(1,IHEP),VHEP(1,IHEP))
69
70	110 CONTINUE
71
72	CALL HWUROF(RBOOST,VTXPIP,VTXPIP)
73
74	C---ENSURE THAT WE ONLY EVER UNBOOST THE SAME EVENT THAT WE BOOSTED
75
76	C (BEARING IN MIND THAT NWGTS IS UPDATED AFTER GENERATING THE WEIGHT)
77
78	BOOSTD=NWGTS+1
79
80	ELSEIF (IOPT.EQ.0) THEN
81
82	IF (BOOSTD.NE.NWGTS) RETURN
83
84	C---UNDO ROTATION AND BOOST
85
86	DO 200 IHEP=1,NHEP
87
88	CALL HWUROB(RBOOST,PHEP(1,IHEP),PHEP(1,IHEP))
89
90	CALL HWULOB(PBOOST,PHEP(1,IHEP),PHEP(1,IHEP))
91
92	CALL HWUROB(RBOOST,VHEP(1,IHEP),VHEP(1,IHEP))
93
94	CALL HWULB4(PBOOST,VHEP(1,IHEP),VHEP(1,IHEP))
95
96	200 CONTINUE
97
98	ENDIF
99
100	END