Visible to Intel only — GUID: GUID-65BCA477-DB53-444B-83A9-0DCEC51D620C
Visible to Intel only — GUID: GUID-65BCA477-DB53-444B-83A9-0DCEC51D620C
?sytri_rook
Computes the inverse of a symmetric matrix using U*D*UT or L*D*LT bounded Bunch-Kaufman factorization.
Syntax
call ssytri_rook( uplo, n, a, lda, ipiv, work, info )
call dsytri_rook( uplo, n, a, lda, ipiv, work, info )
call csytri_rook( uplo, n, a, lda, ipiv, work, info )
call zsytri_rook( uplo, n, a, lda, ipiv, work, info )
call sytri_rook( a, ipiv [,uplo] [,info] )
Include Files
- mkl.fi, lapack.f90
Description
The routine computes the inverse inv(A) of a symmetric matrix A. Before calling this routine, call ?sytrf_rook to factorize A.
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 ssytri_rook DOUBLE PRECISION for dsytri_rook COMPLEX for csytri_rook DOUBLE COMPLEX for zsytri_rook. Arrays: a(size lda by *) contains the factorization of the matrix A, as returned by ?sytrf_rook. The second dimension of a must be at least max(1,n). work(*) is a workspace array. The dimension of work must be at least max(1,n). |
lda |
INTEGER. The leading dimension of a; lda≥ max(1, n). |
ipiv |
INTEGER. Array, size at least max(1, n). The ipiv array, as returned by ?sytrf_rook. |
Output Parameters
a |
Overwritten by the n-by-n matrix inv(A). 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." |
info |
INTEGER. If info = 0, the execution is successful. If info =-i, the i-th parameter had an illegal value. If info = i, the i-th diagonal element of D is zero, D is singular, and the inversion could not be completed. |
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 sytri_rook interface are as follows:
a |
Holds the matrix A of size (n,n). |
ipiv |
Holds the vector of length n. |
uplo |
Must be 'U' or 'L'. The default value is 'U'. |
Application Notes
The total number of floating-point operations is approximately (2/3)n3 for real flavors and (8/3)n3 for complex flavors.