C
C     ..................................................................
C
C        SUBROUTINE QL5
C
C        PURPOSE
C           TO COMPUTE INTEGRAL(EXP(-X)*FCT(X), SUMMED OVER X FROM 0
C                               TO INFINITY).
C
C        USAGE
C           CALL QL5 (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 5-POINT GAUSSIAN-LAGUERRE
C           QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER
C           FCT(X) IS A POLYNOMIAL UP TO DEGREE 9.
C           FOR REFERENCE, SEE
C           V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS,
C           MACMILLAN, NEW YORK/LONDON, 1962, PP.130-132 AND 347-352.
C
C     ..................................................................
C
      SUBROUTINE QL5(FCT,Y)
C
C
      X=12.64080
      Y=.2336997E-4*FCT(X)
      X=7.085810
      Y=Y+.3611759E-2*FCT(X)
      X=3.596426
      Y=Y+.07594245*FCT(X)
      X=1.413403
      Y=Y+.3986668*FCT(X)
      X=.2635603
      Y=Y+.5217556*FCT(X)
      RETURN
      END
