 
      DOUBLE PRECISION FUNCTION DBETAI(X,PIN,QIN)
C***BEGIN PROLOGUE  DBETAI
C***DATE WRITTEN   770701   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C7F
C***KEYWORDS  BETA,BETA FUNCTION,DOUBLE PRECISION,
C             INCOMPLETE BETA FUNCTION,SPECIAL FUNCTION
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Calculates the d.p. incomplete Beta function.
C***DESCRIPTION
C
C DBETAI(X,PIN,QIN) calculates the double precision incomplete beta
C function ratio for double precision arguments X, PIN, and QIN.  It is
C based on Bosten and Battiste, Remark on Algorithm 179, Comm. ACM,
C V 17, P 153, (1974).
C
C             Input Arguments --
C X      upper limit of integration.  X must be in (0,1) inclusive.
C PIN    first beta distribution parameter.  PIN must be .GT. 0.0.
C QIN    second beta distribution parameter.  QIN must be .GT. 0.0.
C DBETAI the incomplete beta function ratio is the probability that a
C        random variable from a beta distribution having parameters
C        PIN and QIN will be less than or equal to X.
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH,DINT,DLBETA,XERROR
C***END PROLOGUE  DBETAI
 
 
