SLATEC Routines --- ZLOG ---

*DECK ZLOG
      SUBROUTINE ZLOG (AR, AI, BR, BI, IERR)
C***BEGIN PROLOGUE  ZLOG
C***SUBSIDIARY
C***PURPOSE  Subsidiary to ZBESH, ZBESI, ZBESJ, ZBESK, ZBESY, ZAIRY and
C            ZBIRY
C***LIBRARY   SLATEC
C***TYPE      ALL (ZLOG-A)
C***AUTHOR  Amos, D. E., (SNL)
C***DESCRIPTION
C
C     DOUBLE PRECISION COMPLEX LOGARITHM B=CLOG(A)
C     IERR=0,NORMAL RETURN      IERR=1, Z=CMPLX(0.0,0.0)
C***SEE ALSO  ZAIRY, ZBESH, ZBESI, ZBESJ, ZBESK, ZBESY, ZBIRY
C***ROUTINES CALLED  ZABS
C***REVISION HISTORY  (YYMMDD)
C   830501  DATE WRITTEN
C   910415  Prologue converted to Version 4.0 format.  (BAB)
C***END PROLOGUE  ZLOG