PROGRAM RPX DEMO C This program demonstrates the use of the coefficients calculated C by the programs axitrx or axistx. The program will produce a table of C values for different values of lambda as set in the DATA statements. C DOUBLE PRECISION DLAMDA(9),RPX,RPX11,RPX12,RPX21,RPX22 INTEGER J DATA DLAMDA/.5D0,1D0,2D0,3D0,4D0,5D0,10D0,20D0,100D0/ WRITE(6,10) 10 FORMAT(1X,' LAMBDA RPX11 RPX12 RPX21 RPX22'/) DO 50 J=1,9 RPX11=RPX(1,1,DLAMDA(J)) RPX12=RPX(1,2,DLAMDA(J)) RPX21=RPX(2,1,DLAMDA(J)) RPX22=RPX(2,2,DLAMDA(J)) 50 WRITE(6,101)DLAMDA(J),RPX11,RPX12,RPX21,RPX22 101 FORMAT(1X,F8.3, 4(F10.5) ) STOP END DOUBLE PRECISION FUNCTION RPX(IALPHA,IBETA,DLAMDA) C ------------------ Arguments of function --------------------------- DOUBLE PRECISION DLAMDA INTEGER IALPHA,IBETA C -------------------------------------------------------------------- C X C This subprogram calculates the functions P defined in C ALPHA BETA C Jeffrey, Phys. Fluids (1992). C ---------------------- Local variables -------------------------------- DOUBLE PRECISION RXPCOF(0:45450) DOUBLE PRECISION G1,G2,G3,G1SUM,G2SUM,G3SUM DOUBLE PRECISION ZL,COEF, XL,XLP1,XL13, XL12 INTEGER I,J,ISTEP,IQ,MMIN,MMAX,M,NM,ISIGN LOGICAL LOADED CHARACTER*4 ID DATA LOADED/.FALSE./ C ---------------------- Start of executable code -------------------- IF(.NOT.LOADED) THEN OPEN(1,FILE='rxp300.dat',STATUS='OLD') READ(1,10) ID,MAXS 10 FORMAT(A4,I5) IF(ID.NE.' RXP') THEN WRITE(*,20) 20 FORMAT(1X,'WRONG COEFFICIENTS FOR RPX') STOP ENDIF READ(1,30) RYpCOF 30 FORMAT(D22.16) CLOSE(1) LOADED=.TRUE. ENDIF IF(DLAMDA.GT.1D0) THEN I=3-IALPHA J=3-IBETA XL=1D0/DLAMDA C RXP and RPX change sign when we invert lambda. ISIGN = -1 ELSE I=IALPHA J=IBETA XL=DLAMDA ISIGN = 1 ENDIF XLP1=XL+1D0 XL12=XLP1**2 XL13=XLP1**3 C These are the g_i for X^G_{11,12} (i=1..3 in paper) IF(I.EQ.1) THEN G1=3D0*XL**2/XL13 G2=3d0*(XL-4D0*XL**2)/(10D0*XL12) G3=(5D0-97D0*XL+64D0*XL**2-44D0*XL**3+XL**4)/(140D0*XL12) ISTEP=1 ELSE C These are the g_i for X^G_{21,22} G1=3D0*XL/XL13 G2=3d0*(XL-4D0)/(10D0*XL12) G3=(5D0*XL**4-97D0*XL**3+64D0*XL**2-44D0*XL+1D0) & /(140D0*XL12*XL**2) C These expressions essentially invert lambda. ISIGN=-ISIGN ISTEP=-1 ENDIF IF(I.NE.J) THEN RPX=0D0-G1/4D0 -G3 MMIN=2 MMAX=MAXS ELSE RPX=G1/4D0+G2*DLOG(4D0)-2D0*G3 MMIN=1 MMAX=MAXS-1 ENDIF G1SUM=G1 G2SUM=2D0*G2 G3SUM=4D0*G3 DO 100 M=MMIN,MMAX,2 IF (ISTEP.GT.0) THEN NM = (M*(M+1))/2 ELSE NM = (M*(M+1))/2 +M ENDIF ZL=XLP1**(-M) COEF=0D0 C Some computers will underflow in the next loop. DO 50 IQ=0,M COEF=COEF+RXPCOF(NM)*ZL NM=NM+ISTEP ZL=ZL*XL 50 CONTINUE RPX=RPX+COEF-G1SUM-(G2SUM-G3SUM/DBLE(M+2))/DBLE(M) 100 CONTINUE RPX = DBLE(ISIGN)*RPX IF(I.EQ.J)RETURN RPX=-RPX*4D0/XLP1**2 IF(I.EQ.2)RPX=RPX*XL**2 RETURN END C BLOCK DATA RPXINI DOUBLE PRECISION RXPCOF(45450) COMMON /XPD250/RXPCOF DATA RXPCOF(1)/0D0/ END