AliDecayer realisation for the EvtGen code and EvtGen itself.

[u/mrichter/AliRoot.git] / TEvtGen / PHOTOS / phoran.F

diff --git a/TEvtGen/PHOTOS/phoran.F b/TEvtGen/PHOTOS/phoran.F
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+      FUNCTION PHORAN(IDUM)
+C.----------------------------------------------------------------------
+C.
+C.    PHOTOS:   PHOton radiation in decays RANdom number generator based
+C.              on Marsaglia Algorithm
+C.
+C.    Purpose:  Generate  uniformly  distributed  random numbers between
+C.              0 and 1.  Super long period:  2**144.  See also:
+C.              G. Marsaglia and A. Zaman,  FSU-SCR-87-50,  for seed mo-
+C.              difications  to  this version  see:  F. James DD-Report,
+C.              November 1988.  The generator  has  to be initialized by
+C.              a call to PHORIN.
+C.
+C.    Input Parameters:   IDUM (integer dummy)
+C.
+C.    Output Parameters:  Function value
+C.
+C.    Author(s):  B. van Eijk, G. Marsaglia and   Created at:  27/09/89
+C.                A. Zaman                        Last Update: 27/09/89
+C.
+C.----------------------------------------------------------------------
+      IMPLICIT NONE
+      REAL*8 PHORAN
+      INTEGER IDUM
+      INTEGER ISEED,I97,J97
+      REAL*8 URAN,CRAN,CDRAN,CMRAN
+      COMMON/PHSEED/ISEED(2),I97,J97,URAN(97),CRAN,CDRAN,CMRAN
+   10 PHORAN=URAN(I97)-URAN(J97)
+      IF (PHORAN.LT.0.D0) PHORAN=PHORAN+1.D0
+      URAN(I97)=PHORAN
+      I97=I97-1
+      IF (I97.EQ.0) I97=97
+      J97=J97-1
+      IF (J97.EQ.0) J97=97
+      CRAN=CRAN-CDRAN
+      IF (CRAN.LT.0.D0) CRAN=CRAN+CMRAN
+      PHORAN=PHORAN-CRAN
+      IF (PHORAN.LT.0.D0) PHORAN=PHORAN+1.D0
+      IF (PHORAN.LE.0.D0) GOTO 10
+      RETURN
+      END