C QL2 10
C ..................................................................QL2 20
C QL2 30
C SUBROUTINE QL2 QL2 40
C QL2 50
C PURPOSE QL2 60
C TO COMPUTE INTEGRAL(EXP(-X)*FCT(X), SUMMED OVER X FROM 0 QL2 70
C TO INFINITY). QL2 80
C QL2 90
C USAGE QL2 100
C CALL QL2 (FCT,Y) QL2 110
C PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT QL2 120
C QL2 130
C DESCRIPTION OF PARAMETERS QL2 140
C FCT - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED. QL2 150
C Y - THE RESULTING INTEGRAL VALUE. QL2 160
C QL2 170
C REMARKS QL2 180
C NONE QL2 190
C QL2 200
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED QL2 210
C THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED QL2 220
C BY THE USER. QL2 230
C QL2 240
C METHOD QL2 250
C EVALUATION IS DONE BY MEANS OF 2-POINT GAUSSIAN-LAGUERRE QL2 260
C QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER QL2 270
C FCT(X) IS A POLYNOMIAL UP TO DEGREE 3. QL2 280
C FOR REFERENCE, SEE QL2 290
C V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS, QL2 300
C MACMILLAN, NEW YORK/LONDON, 1962, PP.130-132 AND 347-352. QL2 310
C QL2 320
C ..................................................................QL2 330
C QL2 340
SUBROUTINE QL2(FCT,Y) QL2 350
C QL2 360
C QL2 370
X=3.414214 QL2 380
Y=.1464466*FCT(X) QL2 390
X=.5857864 QL2 400
Y=Y+.8535534*FCT(X) QL2 410
RETURN QL2 420
END QL2 430