SLATEC Routines --- CPPFA ---

*DECK CPPFA
      SUBROUTINE CPPFA (AP, N, INFO)
C***BEGIN PROLOGUE  CPPFA
C***PURPOSE  Factor a complex Hermitian positive definite matrix stored
C            in packed form.
C***LIBRARY   SLATEC (LINPACK)
C***CATEGORY  D2D1B
C***TYPE      COMPLEX (SPPFA-S, DPPFA-D, CPPFA-C)
C***KEYWORDS  LINEAR ALGEBRA, LINPACK, MATRIX FACTORIZATION, PACKED,
C             POSITIVE DEFINITE
C***AUTHOR  Moler, C. B., (U. of New Mexico)
C***DESCRIPTION
C
C     CPPFA factors a complex Hermitian positive definite matrix
C     stored in packed form.
C
C     CPPFA is usually called by CPPCO, but it can be called
C     directly with a saving in time if  RCOND  is not needed.
C     (Time for CPPCO) = (1 + 18/N)*(Time for CPPFA) .
C
C     On Entry
C
C        AP      COMPLEX (N*(N+1)/2)
C                the packed form of a Hermitian matrix  A .  The
C                columns of the upper triangle are stored sequentially
C                in a one-dimensional array of length  N*(N+1)/2 .
C                See comments below for details.
C
C        N       INTEGER
C                the order of the matrix  A .
C
C     On Return
C
C        AP      an upper triangular matrix  R , stored in packed
C                form, so that  A = CTRANS(R)*R .
C
C        INFO    INTEGER
C                = 0  for normal return.
C                = K  If the leading minor of order  K  is not
C                     positive definite.
C
C
C     Packed Storage
C
C          The following program segment will pack the upper
C          triangle of a Hermitian matrix.
C
C                K = 0
C                DO 20 J = 1, N
C                   DO 10 I = 1, J
C                      K = K + 1
C                      AP(K) = A(I,J)
C             10    CONTINUE
C             20 CONTINUE
C
C***REFERENCES  J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W.
C                 Stewart, LINPACK Users' Guide, SIAM, 1979.
C***ROUTINES CALLED  CDOTC
C***REVISION HISTORY  (YYMMDD)
C   780814  DATE WRITTEN
C   890831  Modified array declarations.  (WRB)
C   890831  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900326  Removed duplicate information from DESCRIPTION section.
C           (WRB)
C   920501  Reformatted the REFERENCES section.  (WRB)
C***END PROLOGUE  CPPFA