dbetai.f
DOUBLE PRECISION FUNCTION DBETAI (X, PIN, QIN)
C***BEGIN PROLOGUE DBETAI
C***PURPOSE Calculate the incomplete Beta function.
C***LIBRARY SLATEC (FNLIB)
C***CATEGORY C7F
C***TYPE DOUBLE PRECISION (BETAI-S, DBETAI-D)
C***KEYWORDS FNLIB, INCOMPLETE BETA FUNCTION, SPECIAL FUNCTIONS
C***AUTHOR Fullerton, W., (LANL)
C***DESCRIPTION
C
C DBETAI calculates the DOUBLE PRECISION incomplete beta function.
C
C The incomplete beta function ratio is the probability that a
C random variable from a beta distribution having parameters PIN and
C QIN will be less than or equal to X.
C
C -- Input Arguments -- All arguments are DOUBLE PRECISION.
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
C***REFERENCES Nancy E. Bosten and E. L. Battiste, Remark on Algorithm
C 179, Communications of the ACM 17, 3 (March 1974),
C pp. 156.
C***ROUTINES CALLED D1MACH, DLBETA, XERMSG
C***REVISION HISTORY (YYMMDD)
C 770701 DATE WRITTEN
C 890531 Changed all specific intrinsics to generic. (WRB)
C 890911 Removed unnecessary intrinsics. (WRB)
C 890911 REVISION DATE from Version 3.2
C 891214 Prologue converted to Version 4.0 format. (BAB)
C 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
C 920528 DESCRIPTION and REFERENCES sections revised. (WRB)
C***END PROLOGUE DBETAI