1
DOUBLE PRECISION FUNCTION bfrac(a,b,x,y,lambda,eps)
2
C-----------------------------------------------------------------------
3
C CONTINUED FRACTION EXPANSION FOR IX(A,B) WHEN A,B .GT. 1.
4
C IT IS ASSUMED THAT LAMBDA = (A + B)*Y - B.
5
C-----------------------------------------------------------------------
6
C .. Scalar Arguments ..
7
DOUBLE PRECISION a,b,eps,lambda,x,y
10
DOUBLE PRECISION alpha,an,anp1,beta,bn,bnp1,c,c0,c1,e,n,p,r,r0,s,
13
C .. External Functions ..
14
DOUBLE PRECISION brcomp
17
C .. Intrinsic Functions ..
20
C .. Executable Statements ..
22
bfrac = brcomp(a,b,x,y)
23
IF (bfrac.EQ.0.0D0) RETURN
39
C CONTINUED FRACTION CALCULATION
45
alpha = (p* (p+c0)*e*e)* (w*x)
46
e = (1.0D0+t)/ (c1+t+t)
47
beta = n + w/s + e* (c+n*yp1)
51
C UPDATE AN, BN, ANP1, AND BNP1
53
t = alpha*an + beta*anp1
56
t = alpha*bn + beta*bnp1
62
IF (abs(r-r0).LE.eps*r) GO TO 20
64
C RESCALE AN, BN, ANP1, AND BNP1