SLATEC Routines --- PPADD ---

*DECK PPADD
      SUBROUTINE PPADD (N, IERROR, A, C, CBP, BP, BH)
C***BEGIN PROLOGUE  PPADD
C***SUBSIDIARY
C***PURPOSE  Subsidiary to BLKTRI
C***LIBRARY   SLATEC
C***TYPE      SINGLE PRECISION (PPADD-S)
C***AUTHOR  (UNKNOWN)
C***DESCRIPTION
C
C   PPADD computes the eigenvalues of the periodic tridiagonal matrix
C   with coefficients AN,BN,CN.
C
C   N    is the order of the BH and BP polynomials.
C   BP   contains the eigenvalues on output.
C   CBP  is the same as BP except type complex.
C   BH   is used to temporarily store the roots of the B HAT polynomial
C        which enters through BP.
C
C***SEE ALSO  BLKTRI
C***ROUTINES CALLED  BSRH, PPSGF, PPSPF, PSGF
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  PPADD