C
C     ..................................................................
C
C        SUBROUTINE QL7
C
C        PURPOSE
C           TO COMPUTE INTEGRAL(EXP(-X)*FCT(X), SUMMED OVER X FROM 0
C                               TO INFINITY).
C
C        USAGE
C           CALL QL7 (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 7-POINT GAUSSIAN-LAGUERRE
C           QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER
C           FCT(X) IS A POLYNOMIAL UP TO DEGREE 13.
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 QL7(FCT,Y)
C
C
      X=19.39573
      Y=.3170315E-7*FCT(X)
      X=12.73418
      Y=Y+.1586546E-4*FCT(X)
      X=8.182153
      Y=Y+.1074010E-2*FCT(X)
      X=4.900353
      Y=Y+.02063351*FCT(X)
      X=2.567877
      Y=Y+.1471263*FCT(X)
      X=1.026665
      Y=Y+.4218313*FCT(X)
      X=.1930437
      Y=Y+.4093190*FCT(X)
      RETURN
      END
