Syntax problems on HP-UX corrected

[u/mrichter/AliRoot.git] / PHOS / shaker / rlu.f

*CMZ :          17/07/98  15.44.33  by  Federico Carminati
*-- Author :
C*********************************************************************

      FUNCTION RLU(IDUM)

C...Purpose: to generate random numbers uniformly distributed between
C...0 and 1, excluding the endpoints.
*KEEP,LUDATR.
      COMMON /LUDATR/ MRLU(6),RRLU(100)
      SAVE /LUDATR/
*KEND.
      EQUIVALENCE (MRLU1,MRLU(1)),(MRLU2,MRLU(2)),(MRLU3,MRLU(3)),
     &(MRLU4,MRLU(4)),(MRLU5,MRLU(5)),(MRLU6,MRLU(6)),
     &(RRLU98,RRLU(98)),(RRLU99,RRLU(99)),(RRLU00,RRLU(100))

C...Initialize generation from given seed.
      IF(MRLU2.EQ.0) THEN
        IJ=MOD(MRLU1/30082,31329)
        KL=MOD(MRLU1,30082)
        I=MOD(IJ/177,177)+2
        J=MOD(IJ,177)+2
        K=MOD(KL/169,178)+1
        L=MOD(KL,169)
        DO 110 II=1,97
        S=0.
        T=0.5
        DO 100 JJ=1,24
        M=MOD(MOD(I*J,179)*K,179)
        I=J
        J=K
        K=M
        L=MOD(53*L+1,169)
        IF(MOD(L*M,64).GE.32) S=S+T
  100   T=0.5*T
  110   RRLU(II)=S
        TWOM24=1.
        DO 120 I24=1,24
  120   TWOM24=0.5*TWOM24
        RRLU98=362436.*TWOM24
        RRLU99=7654321.*TWOM24
        RRLU00=16777213.*TWOM24
        MRLU2=1
        MRLU3=0
        MRLU4=97
        MRLU5=33
      ENDIF

C...Generate next random number.
  130 RUNI=RRLU(MRLU4)-RRLU(MRLU5)
      IF(RUNI.LT.0.) RUNI=RUNI+1.
      RRLU(MRLU4)=RUNI
      MRLU4=MRLU4-1
      IF(MRLU4.EQ.0) MRLU4=97
      MRLU5=MRLU5-1
      IF(MRLU5.EQ.0) MRLU5=97
      RRLU98=RRLU98-RRLU99
      IF(RRLU98.LT.0.) RRLU98=RRLU98+RRLU00
      RUNI=RUNI-RRLU98
      IF(RUNI.LT.0.) RUNI=RUNI+1.
      IF(RUNI.LE.0.OR.RUNI.GE.1.) GOTO 130

C...Update counters. Random number to output.
      MRLU3=MRLU3+1
      IF(MRLU3.EQ.1000000000) THEN
        MRLU2=MRLU2+1
        MRLU3=0
      ENDIF
      RLU=RUNI

      RETURN
      END