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REAL FUNCTION genexp(av)
C**********************************************************************
C
C REAL FUNCTION GENEXP( AV )
C
C GENerate EXPonential random deviate
C
C
C Function
C
C
C Generates a single random deviate from an exponential
C distribution with mean AV.
C
C
C Arguments
C
C
C AV --> The mean of the exponential distribution from which
C a random deviate is to be generated.
C REAL AV
C JJV (AV >= 0)
C
C GENEXP <-- The random deviate.
C REAL GENEXP
C
C
C Method
C
C
C Renames SEXPO from TOMS as slightly modified by BWB to use RANF
C instead of SUNIF.
C
C For details see:
C
C Ahrens, J.H. and Dieter, U.
C Computer Methods for Sampling From the
C Exponential and Normal Distributions.
C Comm. ACM, 15,10 (Oct. 1972), 873 - 882.
C
C**********************************************************************
C .. Scalar Arguments ..
REAL av
C ..
C .. External Functions ..
REAL sexpo
EXTERNAL sexpo
C ..
C .. Executable Statements ..
C JJV added check to ensure AV >= 0.0
IF (av.GE.0.0) GO TO 10
WRITE (*,*) 'AV < 0.0 in GENEXP - ABORT'
WRITE (*,*) 'Value of AV: ',av
STOP 'AV < 0.0 in GENEXP - ABORT'
10 genexp = sexpo()*av
RETURN
END
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