C QTFE 10
C ..................................................................QTFE 20
C QTFE 30
C SUBROUTINE QTFE QTFE 40
C QTFE 50
C PURPOSE QTFE 60
C TO COMPUTE THE VECTOR OF INTEGRAL VALUES FOR A GIVEN QTFE 70
C EQUIDISTANT TABLE OF FUNCTION VALUES. QTFE 80
C QTFE 90
C USAGE QTFE 100
C CALL QTFE (H,Y,Z,NDIM) QTFE 110
C QTFE 120
C DESCRIPTION OF PARAMETERS QTFE 130
C H - THE INCREMENT OF ARGUMENT VALUES. QTFE 140
C Y - THE INPUT VECTOR OF FUNCTION VALUES. QTFE 150
C Z - THE RESULTING VECTOR OF INTEGRAL VALUES. Z MAY BE QTFE 160
C IDENTICAL WITH Y. QTFE 170
C NDIM - THE DIMENSION OF VECTORS Y AND Z. QTFE 180
C QTFE 190
C REMARKS QTFE 200
C NO ACTION IN CASE NDIM LESS THAN 1. QTFE 210
C QTFE 220
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED QTFE 230
C NONE QTFE 240
C QTFE 250
C METHOD QTFE 260
C BEGINNING WITH Z(1)=0, EVALUATION OF VECTOR Z IS DONE BY QTFE 270
C MEANS OF TRAPEZOIDAL RULE (SECOND ORDER FORMULA). QTFE 280
C FOR REFERENCE, SEE QTFE 290
C F.B.HILDEBRAND, INTRODUCTION TO NUMERICAL ANALYSIS, QTFE 300
C MCGRAW-HILL, NEW YORK/TORONTO/LONDON, 1956, PP.75. QTFE 310
C QTFE 320
C ..................................................................QTFE 330
C QTFE 340
SUBROUTINE QTFE(H,Y,Z,NDIM) QTFE 350
C QTFE 360
C QTFE 370
DIMENSION Y(1),Z(1) QTFE 380
C QTFE 390
SUM2=0. QTFE 400
IF(NDIM-1)4,3,1 QTFE 410
1 HH=.5*H QTFE 420
C QTFE 430
C INTEGRATION LOOP QTFE 440
DO 2 I=2,NDIM QTFE 450
SUM1=SUM2 QTFE 460
SUM2=SUM2+HH*(Y(I)+Y(I-1)) QTFE 470
2 Z(I-1)=SUM1 QTFE 480
3 Z(NDIM)=SUM2 QTFE 490
4 RETURN QTFE 500
END QTFE 510