SPPDI(3F)							     SPPDI(3F)

NAME    [Toc]    [Back]

     SPPDI   - SPPDI computes the determinant and inverse of a real symmetric
     positive definite matrix using the	factors	computed by SPPCO or SPPFA .

SYNOPSYS    [Toc]    [Back]

      SUBROUTINE SPPDI(AP,N,DET,JOB)

DESCRIPTION    [Toc]    [Back]

     On	Entry

     AP	REAL (N*(N+1)/2)
	the output from	SPPCO or SPPFA.

     N INTEGER
	the order of the matrix	 A .

     JOB INTEGER
	= 11   both determinant	and inverse.
	= 01   inverse only.
	= 10   determinant only.  On Return

     AP	the upper triangular half of the inverse .
	The strict lower triangle is unaltered.

     DET REAL(2)
	determinant of original	matrix if requested.
	Otherwise not referenced.
	Determinant = DET(1) * 10.0**DET(2)
	with  1.0 .LE. DET(1) .LT. 10.0
	or  DET(1) .EQ.	0.0 .  Error Condition

     A division	by zero	will occur if the input	factor contains	a zero on the
     diagonal and the inverse is requested.  It	will not occur if the
     subroutines are called correctly and if SPOCO or SPOFA has	set INFO .EQ.
     0 .  LINPACK.  This version dated 08/14/78	.  Cleve Moler,	University of
     New Mexico, Argonne National Lab.	Subroutines and	Functions BLAS
     SAXPY,SSCAL Fortran MOD


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