dsytri2x.f - Man Page
SRC/dsytri2x.f
Synopsis
Functions/Subroutines
subroutine dsytri2x (uplo, n, a, lda, ipiv, work, nb, info)
DSYTRI2X
Function/Subroutine Documentation
subroutine dsytri2x (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision, dimension( n+nb+1,* ) work, integer nb, integer info)
DSYTRI2X
Purpose:
DSYTRI2X computes the inverse of a real symmetric indefinite matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by DSYTRF.
- 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.
A
A is DOUBLE PRECISION array, dimension (LDA,N) On entry, the NNB diagonal matrix D and the multipliers used to obtain the factor U or L as computed by DSYTRF. On exit, if INFO = 0, the (symmetric) inverse of the original matrix. If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced; if UPLO = 'L' the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced.
LDA
LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).
IPIV
IPIV is INTEGER array, dimension (N) Details of the interchanges and the NNB structure of D as determined by DSYTRF.
WORK
WORK is DOUBLE PRECISION array, dimension (N+NB+1,NB+3)
NB
NB is INTEGER Block size
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.
Definition at line 119 of file dsytri2x.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page dsytri2x(3) is an alias of dsytri2x.f(3).
Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK