C DFRA 10
C ..................................................................DFRA 20
C DFRA 30
C SUBROUTINE DFRAT DFRA 40
C DFRA 50
C PURPOSE DFRA 60
C DFRAT IS USED FOR HANDLING OF DATA AND FUNDAMENTAL FUNCTIONSDFRA 70
C WITH RATIONAL APPROXIMATION. IT IS A SUBSTANTIAL PART OF DFRA 80
C RATIONAL APPROXIMATION AND HAS NO MEANING INDEPENDENTLY DFRA 90
C DFRA 100
C USAGE DFRA 110
C CALL DFRAT(I,N,M,P,DATI,WGT,IER) DFRA 120
C DFRA 130
C DESCRIPTION OF PARAMETERS DFRA 140
C I - SUBSCRIPT OF CURRENT DATA POINT DFRA 150
C N - NUMBER OF ALL DATA POINTS DFRA 160
C M - NUMBER OF FUNDAMENTAL FUNCTIONS USED DFRA 170
C P - ARRAY OF DIMENSION M+1 AT LEAST, WHICH CONTAINS DFRA 180
C ON RETURN THE VALUES OF THE M FUNDAMENTAL DFRA 190
C FUNCTIONS, FOLLOWED BY CURRENT FUNCTION VALUE DFRA 200
C P MUST BE OF DOUBLE PRECISION DFRA 210
C DATI - ARRAY CONTAINING GIVEN N ARGUMENTS, FOLLOWED DFRA 220
C BY N FUNCTION VALUES AND FINALLY BY 1 RESPECTIVELY DFRA 230
C N WEIGHT VALUES DFRA 240
C DATI MUST BE OF DOUBLE PRECISION DFRA 250
C WGT - RESULTANT WEIGHT FACTOR USED FOR I-TH TERM DFRA 260
C WGT MUST BE OF DOUBLE PRECISION DFRA 270
C IER - RESULTANT ERROR PARAMETER, COMBINED WITH INPUT DFRA 280
C VALUES FOR CONTROL DFRA 290
C IER(2) MEANS DIMENSION OF NUMERATOR DFRA 300
C IER(3) MEANS DIMENSION OF DENOMINATOR DFRA 310
C IER(1) IS USED AS RESULTANT ERROR PARAMETER, DFRA 320
C IER(1) = 0 IN CASE OF NO ERRORS DFRA 330
C IER(1) = 1 OTHERWISE (ZERO DENOMINATOR) DFRA 340
C DFRA 350
C REMARKS DFRA 360
C VECTOR IER IS USED FOR COMMUNICATION BETWEEN DARAT AND DFRATDFRA 370
C DFRA 380
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED DFRA 390
C DCNP DFRA 400
C DFRA 410
C METHOD DFRA 420
C CF. MATHEMATICAL DESCRIPTION OF SUBROUTINE ARAT DFRA 430
C DFRA 440
C ..................................................................DFRA 450
C DFRA 460
SUBROUTINE DFRAT(I,N,M,P,DATI,WGT,IER) DFRA 470
C DFRA 480
C DFRA 490
C DIMENSIONED DUMMY VARIABLES DFRA 500
DIMENSION P(1),DATI(1),IER(1) DFRA 510
DOUBLE PRECISION P,DATI,WGT,T,F,FNUM,FDEN DFRA 520
C DFRA 530
C INITIALIZATION DFRA 540
IP=IER(2) DFRA 550
IQ=IER(3) DFRA 560
IQM1=IQ-1 DFRA 570
IPQ=IP+IQ DFRA 580
C DFRA 590
C LOOK UP ARGUMENT, FUNCTION VALUE AND WEIGHT DFRA 600
C LOOK UP NUMERATOR AND DENOMINATOR DFRA 610
T=DATI(I) DFRA 620
J=I+N DFRA 630
F=DATI(J) DFRA 640
FNUM=P(J) DFRA 650
J=J+N DFRA 660
WGT=1.D0 DFRA 670
IF(DATI(2*N+1))2,2,1 DFRA 680
1 WGT=DATI(J) DFRA 690
2 FDEN=P(J) DFRA 700
C DFRA 710
C CALCULATE FUNCTION VALUE USED DFRA 720
F=F*FDEN-FNUM DFRA 730
C DFRA 740
C CHECK FOR ZERO DENOMINATOR DFRA 750
IF(FDEN)4,3,4 DFRA 760
C DFRA 770
C ERROR RETURN IN CASE OF ZERO DENOMINATOR DFRA 780
3 IER(1)=1 DFRA 790
RETURN DFRA 800
C DFRA 810
C CALCULATE WEIGHT FACTORS USED DFRA 820
4 WGT=WGT/(FDEN*FDEN) DFRA 830
FNUM=-FNUM/FDEN DFRA 840
C DFRA 850
C CALCULATE FUNDAMENTAL FUNCTIONS DFRA 860
J=IQM1 DFRA 870
IF(IP-IQ)6,6,5 DFRA 880
5 J=IP-1 DFRA 890
6 CALL DCNP(P(IQ),T,J) DFRA 900
C DFRA 910
C STORE VALUES OF DENOMINATOR FUNDAMENTAL FUNCTIONS DFRA 920
7 IF(IQM1)10,10,8 DFRA 930
8 DO 9 II=1,IQM1 DFRA 940
J=II+IQ DFRA 950
9 P(II)=P(J)*FNUM DFRA 960
C DFRA 970
C STORE FUNCTION VALUE DFRA 980
10 P(IPQ)=F DFRA 990
C DFRA1000
C NORMAL RETURN DFRA1010
IER(1)=0 DFRA1020
RETURN DFRA1030
END DFRA1040