SLATEC Routines --- COMPB ---

*DECK COMPB
      SUBROUTINE COMPB (N, IERROR, AN, BN, CN, B, AH, BH)
C***BEGIN PROLOGUE  COMPB
C***SUBSIDIARY
C***PURPOSE  Subsidiary to BLKTRI
C***LIBRARY   SLATEC
C***TYPE      SINGLE PRECISION (COMPB-S, CCMPB-C)
C***AUTHOR  (UNKNOWN)
C***DESCRIPTION
C
C     COMPB computes the roots of the B polynomials using subroutine
C     TEVLS which is a modification the EISPACK program TQLRAT.
C     IERROR is set to 4 if either TEVLS fails or if A(J+1)*C(J) is
C     less than zero for some J.  AH,BH are temporary work arrays.
C
C***SEE ALSO  BLKTRI
C***ROUTINES CALLED  INDXB, PPADD, R1MACH, TEVLS
C***COMMON BLOCKS    CBLKT
C***REVISION HISTORY  (YYMMDD)
C   801001  DATE WRITTEN
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900402  Added TYPE section.  (WRB)
C***END PROLOGUE  COMPB