dsptri(l) [redhat man page]

DSPTRI(l)								 )								 DSPTRI(l)

NAME

       DSPTRI - compute the inverse of a real symmetric indefinite matrix A in packed storage using the factorization A = U*D*U**T or A = L*D*L**T
       computed by DSPTRF

SYNOPSIS

       SUBROUTINE DSPTRI( UPLO, N, AP, IPIV, WORK, INFO )

	   CHARACTER	  UPLO

	   INTEGER	  INFO, N

	   INTEGER	  IPIV( * )

	   DOUBLE	  PRECISION AP( * ), WORK( * )

PURPOSE

       DSPTRI computes the inverse of a real symmetric indefinite matrix A in packed storage using the factorization A = U*D*U**T or A =  L*D*L**T
       computed by DSPTRF.

ARGUMENTS

       UPLO    (input) CHARACTER*1
	       Specifies  whether  the	details of the factorization are stored as an upper or lower triangular matrix.  = 'U':  Upper triangular,
	       form is A = U*D*U**T;
	       = 'L':  Lower triangular, form is A = L*D*L**T.

       N       (input) INTEGER
	       The order of the matrix A.  N >= 0.

       AP      (input/output) DOUBLE PRECISION array, dimension (N*(N+1)/2)
	       On entry, the block diagonal matrix D and the multipliers used to obtain the factor U or L as  computed	by  DSPTRF,  stored  as  a
	       packed triangular matrix.

	       On  exit,  if  INFO  =  0, the (symmetric) inverse of the original matrix, stored as a packed triangular matrix. The j-th column of
	       inv(A) is stored in the array AP as follows: if UPLO = 'U', AP(i + (j-1)*j/2) = inv(A)(i,j) for 1<=i<=j; if  UPLO  =  'L',  AP(i  +
	       (j-1)*(2n-j)/2) = inv(A)(i,j) for j<=i<=n.

       IPIV    (input) INTEGER array, dimension (N)
	       Details of the interchanges and the block structure of D as determined by DSPTRF.

       WORK    (workspace) DOUBLE PRECISION array, dimension (N)

       INFO    (output) INTEGER
	       = 0: successful exit
	       < 0: if INFO = -i, the i-th argument had an illegal value
	       > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its inverse could not be computed.

LAPACK version 3.0						   15 June 2000 							 DSPTRI(l)

dsptri.f(3)							      LAPACK							       dsptri.f(3)

NAME

       dsptri.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dsptri (UPLO, N, AP, IPIV, WORK, INFO)
	   DSPTRI

Function/Subroutine Documentation
   subroutine dsptri (characterUPLO, integerN, double precision, dimension( * )AP, integer, dimension( * )IPIV, double precision, dimension( *
       )WORK, integerINFO)
       DSPTRI

       Purpose:

	    DSPTRI computes the inverse of a real symmetric indefinite matrix
	    A in packed storage using the factorization A = U*D*U**T or
	    A = L*D*L**T computed by DSPTRF.

       Parameters:
	   UPLO

		     UPLO is CHARACTER*1
		     Specifies whether the details of the factorization are stored
		     as an upper or lower triangular matrix.
		     = 'U':  Upper triangular, form is A = U*D*U**T;
		     = 'L':  Lower triangular, form is A = L*D*L**T.

	   N

		     N is INTEGER
		     The order of the matrix A.  N >= 0.

	   AP

		     AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
		     On entry, the block diagonal matrix D and the multipliers
		     used to obtain the factor U or L as computed by DSPTRF,
		     stored as a packed triangular matrix.

		     On exit, if INFO = 0, the (symmetric) inverse of the original
		     matrix, stored as a packed triangular matrix. The j-th column
		     of inv(A) is stored in the array AP as follows:
		     if UPLO = 'U', AP(i + (j-1)*j/2) = inv(A)(i,j) for 1<=i<=j;
		     if UPLO = 'L',
			AP(i + (j-1)*(2n-j)/2) = inv(A)(i,j) for j<=i<=n.

	   IPIV

		     IPIV is INTEGER array, dimension (N)
		     Details of the interchanges and the block structure of D
		     as determined by DSPTRF.

	   WORK

		     WORK is DOUBLE PRECISION array, dimension (N)

	   INFO

		     INFO is INTEGER
		     = 0: successful exit
		     < 0: if INFO = -i, the i-th argument had an illegal value
		     > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its
			  inverse could not be computed.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 110 of file dsptri.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       dsptri.f(3)