Visible to Intel only — GUID: GUID-E789C810-50C8-414F-9CF9-9E3A6AB61FED
Visible to Intel only — GUID: GUID-E789C810-50C8-414F-9CF9-9E3A6AB61FED
?sytri2x
Computes the inverse of a symmetric indefinite matrix after ?sytri2sets the leading dimension of the workspace.
Syntax
call ssytri2x( uplo, n, a, lda, ipiv, work, nb, info )
call dsytri2x( uplo, n, a, lda, ipiv, work, nb, info )
call csytri2x( uplo, n, a, lda, ipiv, work, nb, info )
call zsytri2x( uplo, n, a, lda, ipiv, work, nb, info )
call sytri2x( a,ipiv,nb[,uplo][,info] )
Include Files
- mkl.fi, lapack.f90
Description
The routine computes the inverse inv(A) of a symmetric indefinite matrix A using the factorization A = U*D*UT or A = L*D*LT computed by ?sytrf.
The ?sytri2x actually computes the inverse after the ?sytri2 routine sets the leading dimension of the workspace before calling ?sytri2x.
Input Parameters
uplo |
CHARACTER*1. Must be 'U' or 'L'. Indicates how the input matrix A has been factored: If uplo = 'U', the array a stores the factorization A = U*D*UT. If uplo = 'L', the array a stores the factorization A = L*D*LT. |
n |
INTEGER. The order of the matrix A; n≥ 0. |
a, work |
REAL for ssytri2x DOUBLE PRECISION for dsytri2x COMPLEX for csytri2x DOUBLE COMPLEX for zsytri2x Arrays: a(lda,*) contains the nb (block size) diagonal matrix D and the multipliers used to obtain the factor U or L as returned by ?sytrf. The second dimension of a must be at least max(1,n). work is a workspace array of dimension (n+nb+1)*(nb+3) where nb is the block size as set by ?sytrf. |
lda |
INTEGER. The leading dimension of a; lda≥ max(1, n). |
ipiv |
INTEGER. Array, size at least max(1, n). Details of the interchanges and the nb structure of D as returned by ?sytrf. |
nb |
INTEGER. Block size. |
Output Parameters
a |
If info = 0, the symmetric inverse of the original matrix. If info = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced. If info = 'L', the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced. |
info |
INTEGER. If info = 0, the execution is successful. If info =-i, the i-th parameter had an illegal value. If info = i, Dii= 0; D is singular and its inversion could not be computed. |
LAPACK 95 Interface Notes
Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see LAPACK 95 Interface Conventions.
Specific details for the routine sytri2x interface are as follows:
a |
Holds the matrix A of size (n,n). |
ipiv |
Holds the vector of length n. |
nb |
Holds the block size. |
uplo |
Indicates how the input matrix A has been factored. Must be 'U' or 'L'. |