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