C QG5 10
C ..................................................................QG5 20
C QG5 30
C SUBROUTINE QG5 QG5 40
C QG5 50
C PURPOSE QG5 60
C TO COMPUTE INTEGRAL(FCT(X), SUMMED OVER X FROM XL TO XU) QG5 70
C QG5 80
C USAGE QG5 90
C CALL QG5 (XL,XU,FCT,Y) QG5 100
C PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT QG5 110
C QG5 120
C DESCRIPTION OF PARAMETERS QG5 130
C XL - THE LOWER BOUND OF THE INTERVAL. QG5 140
C XU - THE UPPER BOUND OF THE INTERVAL. QG5 150
C FCT - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED. QG5 160
C Y - THE RESULTING INTEGRAL VALUE. QG5 170
C QG5 180
C REMARKS QG5 190
C NONE QG5 200
C QG5 210
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED QG5 220
C THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED QG5 230
C BY THE USER. QG5 240
C QG5 250
C METHOD QG5 260
C EVALUATION IS DONE BY MEANS OF 5-POINT GAUSS QUADRATURE QG5 270
C FORMULA, WHICH INTEGRATES POLYNOMIALS UP TO DEGREE 9 QG5 280
C EXACTLY. QG5 290
C FOR REFERENCE, SEE QG5 300
C V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS, QG5 310
C MACMILLAN, NEW YORK/LONDON, 1962, PP.100-111 AND 337-338. QG5 320
C QG5 330
C ..................................................................QG5 340
C QG5 350
SUBROUTINE QG5(XL,XU,FCT,Y) QG5 360
C QG5 370
C QG5 380
A=.5*(XU+XL) QG5 390
B=XU-XL QG5 400
C=.4530899*B QG5 410
Y=.1184634*(FCT(A+C)+FCT(A-C)) QG5 420
C=.2692347*B QG5 430
Y=Y+.2393143*(FCT(A+C)+FCT(A-C)) QG5 440
Y=B*(Y+.2844444*FCT(A)) QG5 450
RETURN QG5 460
END QG5 470