C
C     ..................................................................
C
C        SUBROUTINE QA6
C
C        PURPOSE
C           TO COMPUTE INTEGRAL(EXP(-X)*FCT(X)/SQRT(X), SUMMED OVER X
C                               FROM 0 TO INFINITY).
C
C        USAGE
C           CALL QA6 (FCT,Y)
C           PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT
C
C        DESCRIPTION OF PARAMETERS
C           FCT    - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED.
C           Y      - THE RESULTING INTEGRAL VALUE.
C
C        REMARKS
C           NONE
C
C        SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED
C           THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED
C           BY THE USER.
C
C        METHOD
C           EVALUATION IS DONE BY MEANS OF 6-POINT GENERALIZED GAUSSIAN-
C           LAGUERRE QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY,
C           WHENEVER FCT(X) IS A POLYNOMIAL UP TO DEGREE 11.
C           FOR REFERENCE, SEE
C           CONCUS/CASSATT/JAEHNIG/MELBY, TABLES FOR THE EVALUATION OF
C           INTEGRAL(X**BETA*EXP(-X)*F(X), SUMMED OVER X FROM 0 TO
C           INFINITY) BY GAUSS-LAGUERRE QUADRATURE, MTAC, VOL.17,
C           ISS.83 (1963), PP.245-256.
C
C     ..................................................................
C
      SUBROUTINE QA6(FCT,Y)
C
C
      X=15.12996
      Y=.5317103E-6*FCT(X)
      X=9.124248
      Y=Y+.0001714737*FCT(X)
      X=5.196153
      Y=Y+.007810781*FCT(X)
      X=2.552590
      Y=Y+.1032160*FCT(X)
      X=.8983028
      Y=Y+.5209846*FCT(X)
      X=.09874701
      Y=Y+1.140270*FCT(X)
      RETURN
      END
