C QH2 10
C ..................................................................QH2 20
C QH2 30
C SUBROUTINE QH2 QH2 40
C QH2 50
C PURPOSE QH2 60
C TO COMPUTE INTEGRAL(EXP(-X*X)*FCT(X), SUMMED OVER X FROM QH2 70
C -INFINITY TO +INFINITY). QH2 80
C QH2 90
C USAGE QH2 100
C CALL QH2 (FCT,Y) QH2 110
C PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT QH2 120
C QH2 130
C DESCRIPTION OF PARAMETERS QH2 140
C FCT - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED. QH2 150
C Y - THE RESULTING INTEGRAL VALUE. QH2 160
C QH2 170
C REMARKS QH2 180
C NONE QH2 190
C QH2 200
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED QH2 210
C THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED QH2 220
C BY THE USER. QH2 230
C QH2 240
C METHOD QH2 250
C EVALUATION IS DONE BY MEANS OF 2-POINT GAUSSIAN-HERMITE QH2 260
C QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER QH2 270
C FCT(X) IS A POLYNOMIAL UP TO DEGREE 3. QH2 280
C FOR REFERENCE, SEE QH2 290
C V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS, QH2 300
C MACMILLAN, NEW YORK/LONDON, 1962, PP.129-130 AND 343-346. QH2 310
C QH2 320
C ..................................................................QH2 330
C QH2 340
SUBROUTINE QH2(FCT,Y) QH2 350
C QH2 360
C QH2 370
X=.7071068 QH2 380
Z=-X QH2 390
Y=.8862269*(FCT(X)+FCT(Z)) QH2 400
RETURN QH2 410
END QH2 420