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