C QH4 10
C ..................................................................QH4 20
C QH4 30
C SUBROUTINE QH4 QH4 40
C QH4 50
C PURPOSE QH4 60
C TO COMPUTE INTEGRAL(EXP(-X*X)*FCT(X), SUMMED OVER X FROM QH4 70
C -INFINITY TO +INFINITY). QH4 80
C QH4 90
C USAGE QH4 100
C CALL QH4 (FCT,Y) QH4 110
C PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT QH4 120
C QH4 130
C DESCRIPTION OF PARAMETERS QH4 140
C FCT - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED. QH4 150
C Y - THE RESULTING INTEGRAL VALUE. QH4 160
C QH4 170
C REMARKS QH4 180
C NONE QH4 190
C QH4 200
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED QH4 210
C THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED QH4 220
C BY THE USER. QH4 230
C QH4 240
C METHOD QH4 250
C EVALUATION IS DONE BY MEANS OF 4-POINT GAUSSIAN-HERMITE QH4 260
C QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER QH4 270
C FCT(X) IS A POLYNOMIAL UP TO DEGREE 7. QH4 280
C FOR REFERENCE, SEE QH4 290
C V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS, QH4 300
C MACMILLAN, NEW YORK/LONDON, 1962, PP.129-130 AND 343-346. QH4 310
C QH4 320
C ..................................................................QH4 330
C QH4 340
SUBROUTINE QH4(FCT,Y) QH4 350
C QH4 360
C QH4 370
X=1.650680 QH4 380
Z=-X QH4 390
Y=.08131284*(FCT(X)+FCT(Z)) QH4 400
X=.5246476 QH4 410
Z=-X QH4 420
Y=Y+.8049141*(FCT(X)+FCT(Z)) QH4 430
RETURN QH4 440
END QH4 450