dsytri2.f - Man Page
Synopsis
Functions/Subroutines
subroutine dsytri2 (UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO)
DSYTRI2
Function/Subroutine Documentation
subroutine dsytri2 (character UPLO, integer N, double precision, dimension( lda, * ) A, integer LDA, integer, dimension( * ) IPIV, double precision, dimension( * ) WORK, integer LWORK, integer INFO)
DSYTRI2
Purpose:
DSYTRI2 computes the inverse of a DOUBLE PRECISION symmetric indefinite matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by DSYTRF. DSYTRI2 sets the LEADING DIMENSION of the workspace before calling DSYTRI2X that actually computes the inverse.
- 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 NB 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 NB structure of D as determined by DSYTRF.
WORK
WORK is DOUBLE PRECISION array, dimension (N+NB+1)*(NB+3)
LWORK
LWORK is INTEGER The dimension of the array WORK. WORK is size >= (N+NB+1)*(NB+3) If LDWORK = -1, then a workspace query is assumed; the routine calculates: - the optimal size of the WORK array, returns this value as the first entry of the WORK array, - and no error message related to LDWORK is issued by XERBLA.
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 2017
Definition at line 129 of file dsytri2.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Referenced By
The man page dsytri2(3) is an alias of dsytri2.f(3).
Tue Nov 14 2017 Version 3.8.0 LAPACK