SLATEC Routines --- ZSERI ---

*DECK ZSERI
      SUBROUTINE ZSERI (ZR, ZI, FNU, KODE, N, YR, YI, NZ, TOL, ELIM,
     +   ALIM)
C***BEGIN PROLOGUE  ZSERI
C***SUBSIDIARY
C***PURPOSE  Subsidiary to ZBESI and ZBESK
C***LIBRARY   SLATEC
C***TYPE      ALL (CSERI-A, ZSERI-A)
C***AUTHOR  Amos, D. E., (SNL)
C***DESCRIPTION
C
C     ZSERI COMPUTES THE I BESSEL FUNCTION FOR REAL(Z).GE.0.0 BY
C     MEANS OF THE POWER SERIES FOR LARGE ABS(Z) IN THE
C     REGION ABS(Z).LE.2*SQRT(FNU+1). NZ=0 IS A NORMAL RETURN.
C     NZ.GT.0 MEANS THAT THE LAST NZ COMPONENTS WERE SET TO ZERO
C     DUE TO UNDERFLOW. NZ.LT.0 MEANS UNDERFLOW OCCURRED, BUT THE
C     CONDITION ABS(Z).LE.2*SQRT(FNU+1) WAS VIOLATED AND THE
C     COMPUTATION MUST BE COMPLETED IN ANOTHER ROUTINE WITH N=N-ABS(NZ).
C
C***SEE ALSO  ZBESI, ZBESK
C***ROUTINES CALLED  D1MACH, DGAMLN, ZABS, ZDIV, ZLOG, ZMLT, ZUCHK
C***REVISION HISTORY  (YYMMDD)
C   830501  DATE WRITTEN
C   910415  Prologue converted to Version 4.0 format.  (BAB)
C   930122  Added ZLOG to EXTERNAL statement.  (RWC)
C***END PROLOGUE  ZSERI