C QL4 10
C ..................................................................QL4 20
C QL4 30
C SUBROUTINE QL4 QL4 40
C QL4 50
C PURPOSE QL4 60
C TO COMPUTE INTEGRAL(EXP(-X)*FCT(X), SUMMED OVER X FROM 0 QL4 70
C TO INFINITY). QL4 80
C QL4 90
C USAGE QL4 100
C CALL QL4 (FCT,Y) QL4 110
C PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT QL4 120
C QL4 130
C DESCRIPTION OF PARAMETERS QL4 140
C FCT - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED. QL4 150
C Y - THE RESULTING INTEGRAL VALUE. QL4 160
C QL4 170
C REMARKS QL4 180
C NONE QL4 190
C QL4 200
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED QL4 210
C THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED QL4 220
C BY THE USER. QL4 230
C QL4 240
C METHOD QL4 250
C EVALUATION IS DONE BY MEANS OF 4-POINT GAUSSIAN-LAGUERRE QL4 260
C QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER QL4 270
C FCT(X) IS A POLYNOMIAL UP TO DEGREE 7. QL4 280
C FOR REFERENCE, SEE QL4 290
C V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS, QL4 300
C MACMILLAN, NEW YORK/LONDON, 1962, PP.130-132 AND 347-352. QL4 310
C QL4 320
C ..................................................................QL4 330
C QL4 340
SUBROUTINE QL4(FCT,Y) QL4 350
C QL4 360
C QL4 370
X=9.395071 QL4 380
Y=.5392947E-3*FCT(X) QL4 390
X=4.536620 QL4 400
Y=Y+.03888791*FCT(X) QL4 410
X=1.745761 QL4 420
Y=Y+.3574187*FCT(X) QL4 430
X=.3225477 QL4 440
Y=Y+.6031541*FCT(X) QL4 450
RETURN QL4 460
END QL4 470