C DTSG 10
C ..................................................................DTSG 20
C DTSG 30
C SUBROUTINE DATSG DTSG 40
C DTSG 50
C PURPOSE DTSG 60
C NDIM POINTS OF A GIVEN GENERAL TABLE ARE SELECTED AND DTSG 70
C ORDERED SUCH THAT ABS(ARG(I)-X).GE.ABS(ARG(J)-X) IF I.GT.J. DTSG 80
C DTSG 90
C USAGE DTSG 100
C CALL DATSG (X,Z,F,WORK,IROW,ICOL,ARG,VAL,NDIM) DTSG 110
C DTSG 120
C DESCRIPTION OF PARAMETERS DTSG 130
C X - DOUBLE PRECISION SEARCH ARGUMENT. DTSG 140
C Z - DOUBLE PRECISION VECTOR OD ARGUMENT VALUES DTSG 150
C (DIMENSION IROW). DTSG 160
C F - IN CASE ICOL=1, F IS THE DOUBLE PRECISION VECTOR DTSG 170
C OF FUNCTION VALUES (DIMENSION IROW). DTSG 180
C IN CASE ICOL=2, F IS A DOUBLE PRECISION IROW BY 2 DTSG 190
C MATRIX. THE FIRST COLUMN SPECIFIES VECTOR OF FUNC- DTSG 200
C TION VALUES AND THE SECOND VECTOR OF DERIVATIVES. DTSG 210
C WORK - DOUBLE PRECISION WORKING STORAGE (DIMENSION IROW). DTSG 220
C IROW - THE DIMENSION OF VECTORS Z AND WORK AND OF EACH DTSG 230
C COLUMN IN MATRIX F. DTSG 240
C ICOL - THE NUMBER OF COLUMNS IN F (I.E. 1 OR 2). DTSG 250
C ARG - RESULTING DOUBLE PRECISION VECTOR OF SELECTED AND DTSG 260
C ORDERED ARGUMENT VALUES (DIMENSION NDIM). DTSG 270
C VAL - RESULTING DOUBLE PRECISION VECTOR OF SELECTED DTSG 280
C FUNCTION VALUES (DIMENSION NDIM) IN CASE ICOL=1. DTSG 290
C IN CASE ICOL=2, VAL IS THE DOUBLE PRECISION VECTOR DTSG 300
C OF FUNCTION AND DERIVATIVE VALUES (DIMENSION DTSG 310
C 2*NDIM) WHICH ARE STORED IN PAIRS (I.E. EACH FUNC- DTSG 320
C TION VALUE IS FOLLOWED BY ITS DERIVATIVE VALUE). DTSG 330
C NDIM - THE NUMBER OF POINTS WHICH MUST BE SELECTED OUT OF DTSG 340
C THE GIVEN TABLE (Z,F). DTSG 350
C DTSG 360
C REMARKS DTSG 370
C NO ACTION IN CASE IROW LESS THAN 1. DTSG 380
C IF INPUT VALUE NDIM IS GREATER THAN IROW, THE PROGRAM DTSG 390
C SELECTS ONLY A MAXIMUM TABLE OF IROW POINTS. THEREFORE THE DTSG 400
C USER OUGHT TO CHECK CORRESPONDENCE BETWEEN TABLE (ARG,VAL) DTSG 410
C AND ITS DIMENSION BY COMPARISON OF NDIM AND IROW, IN ORDER DTSG 420
C TO GET CORRECT RESULTS IN FURTHER WORK WITH TABLE (ARG,VAL).DTSG 430
C THIS TEST MAY BE DONE BEFORE OR AFTER CALLING DTSG 440
C SUBROUTINE DATSG. DTSG 450
C SUBROUTINE DATSG ESPECIALLY CAN BE USED FOR GENERATING THE DTSG 460
C TABLE (ARG,VAL) NEEDED IN SUBROUTINES DALI, DAHI, AND DACFI.DTSG 470
C DTSG 480
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED DTSG 490
C NONE DTSG 500
C DTSG 510
C METHOD DTSG 520
C SELECTION IS DONE BY GENERATING THE VECTOR WORK WITH DTSG 530
C COMPONENTS WORK(I)=ABS(Z(I)-X) AND AT EACH OF THE NDIM STEPSDTSG 540
C (OR IROW STEPS IF NDIM IS GREATER THAN IROW) DTSG 550
C SEARCHING FOR THE SUBSCRIPT OF THE SMALLEST COMPONENT, WHICHDTSG 560
C IS AFTERWARDS REPLACED BY A NUMBER GREATER THAN DTSG 570
C MAX(WORK(I)). DTSG 580
C DTSG 590
C ..................................................................DTSG 600
C DTSG 610
SUBROUTINE DATSG(X,Z,F,WORK,IROW,ICOL,ARG,VAL,NDIM) DTSG 620
C DTSG 630
C DTSG 640
DIMENSION Z(1),F(1),WORK(1),ARG(1),VAL(1) DTSG 650
DOUBLE PRECISION X,Z,F,WORK,ARG,VAL,B,DELTA DTSG 660
IF(IROW)11,11,1 DTSG 670
1 N=NDIM DTSG 680
C IF N IS GREATER THAN IROW, N IS SET EQUAL TO IROW. DTSG 690
IF(N-IROW)3,3,2 DTSG 700
2 N=IROW DTSG 710
C DTSG 720
C GENERATION OF VECTOR WORK AND COMPUTATION OF ITS GREATEST ELEMENT.DTSG 730
3 B=0.D0 DTSG 740
DO 5 I=1,IROW DTSG 750
DELTA=DABS(Z(I)-X) DTSG 760
IF(DELTA-B)5,5,4 DTSG 770
4 B=DELTA DTSG 780
5 WORK(I)=DELTA DTSG 790
C DTSG 800
C GENERATION OF TABLE (ARG,VAL) DTSG 810
B=B+1.D0 DTSG 820
DO 10 J=1,N DTSG 830
DELTA=B DTSG 840
DO 7 I=1,IROW DTSG 850
IF(WORK(I)-DELTA)6,7,7 DTSG 860
6 II=I DTSG 870
DELTA=WORK(I) DTSG 880
7 CONTINUE DTSG 890
ARG(J)=Z(II) DTSG 900
IF(ICOL-1)8,9,8 DTSG 910
8 VAL(2*J-1)=F(II) DTSG 920
III=II+IROW DTSG 930
VAL(2*J)=F(III) DTSG 940
GOTO 10 DTSG 950
9 VAL(J)=F(II) DTSG 960
10 WORK(II)=B DTSG 970
11 RETURN DTSG 980
END DTSG 990