 
      SUBROUTINE DPPDI(AP,N,DET,JOB)
C***BEGIN PROLOGUE  DPPDI
C***DATE WRITTEN   780814   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  D2B1B,D3B1B
C***KEYWORDS  DETERMINANT,DOUBLE PRECISION,FACTOR,INVERSE,
C             LINEAR ALGEBRA,LINPACK,MATRIX,PACKED,POSITIVE DEFINITE
C***AUTHOR  MOLER, C. B., (U. OF NEW MEXICO)
C***PURPOSE  Computes the determinant and inverse of a d.p. SYMMETRIC
C            POSITIVE DEFINITE matrix using factors from DPPCO or DPPFA.
C***DESCRIPTION
C
C     DPPDI computes the determinant and inverse
C     of a double precision symmetric positive definite matrix
C     using the factors computed by DPPCO or DPPFA .
C
C     On Entry
C
C        AP      DOUBLE PRECISION (N*(N+1)/2)
C                the output from DPPCO or DPPFA.
C
C        N       INTEGER
C                the order of the matrix  A .
C
C        JOB     INTEGER
C                = 11   both determinant and inverse.
C                = 01   inverse only.
C                = 10   determinant only.
C
C     On Return
C
C        AP      the upper triangular half of the inverse .
C                The strict lower triangle is unaltered.
C
C        DET     DOUBLE PRECISION(2)
C                determinant of original matrix if requested.
C                Otherwise not referenced.
C                DETERMINANT = DET(1) * 10.0**DET(2)
C                with  1.0 .LE. DET(1) .LT. 10.0
C                or  DET(1) .EQ. 0.0 .
C
C     Error Condition
C
C        A division by zero will occur if the input factor contains
C        a zero on the diagonal and the inverse is requested.
C        It will not occur if the subroutines are called correctly
C        and if DPOCO or DPOFA has set INFO .EQ. 0 .
C
C     LINPACK.  This version dated 08/14/78 .
C     Cleve Moler, University of New Mexico, Argonne National Lab.
C
C     Subroutines and Functions
C
C     BLAS DAXPY,DSCAL
C     Fortran MOD
C***REFERENCES  DONGARRA J.J., BUNCH J.R., MOLER C.B., STEWART G.W.,
C                 *LINPACK USERS  GUIDE*, SIAM, 1979.
C***ROUTINES CALLED  DAXPY,DSCAL
C***END PROLOGUE  DPPDI
 
 
