zrati.f
SUBROUTINE ZRATI (ZR, ZI, FNU, N, CYR, CYI, TOL)
C***BEGIN PROLOGUE ZRATI
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Warning: this routine is not intended to be user-callable.
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C***SUBSIDIARY
C***PURPOSE Subsidiary to ZBESH, ZBESI and ZBESK
C***LIBRARY SLATEC
C***TYPE ALL (CRATI-A, ZRATI-A)
C***AUTHOR Amos, D. E., (SNL)
C***DESCRIPTION
C
C ZRATI COMPUTES RATIOS OF I BESSEL FUNCTIONS BY BACKWARD
C RECURRENCE. THE STARTING INDEX IS DETERMINED BY FORWARD
C RECURRENCE AS DESCRIBED IN J. RES. OF NAT. BUR. OF STANDARDS-B,
C MATHEMATICAL SCIENCES, VOL 77B, P111-114, SEPTEMBER, 1973,
C BESSEL FUNCTIONS I AND J OF COMPLEX ARGUMENT AND INTEGER ORDER,
C BY D. J. SOOKNE.
C
C***SEE ALSO ZBESH, ZBESI, ZBESK
C***ROUTINES CALLED ZABS, ZDIV
C***REVISION HISTORY (YYMMDD)
C 830501 DATE WRITTEN
C 910415 Prologue converted to Version 4.0 format. (BAB)
C***END PROLOGUE ZRATI