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LAPACK: Linear Algebra PACKage
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ssytri2x.f File Reference

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Functions/Subroutines

subroutine ssytri2x (UPLO, N, A, LDA, IPIV, WORK, NB, INFO)
 SSYTRI2X More...
 

Function/Subroutine Documentation

subroutine ssytri2x ( character  UPLO,
integer  N,
real, dimension( lda, * )  A,
integer  LDA,
integer, dimension( * )  IPIV,
real, dimension( n+nb+1,* )  WORK,
integer  NB,
integer  INFO 
)

SSYTRI2X

Download SSYTRI2X + dependencies [TGZ] [ZIP] [TXT]
Purpose:
 SSYTRI2X 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
 SSYTRF.
Parameters
[in]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.
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in,out]A
          A is REAL 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 SSYTRF.

          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.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,N).
[in]IPIV
          IPIV is INTEGER array, dimension (N)
          Details of the interchanges and the NNB structure of D
          as determined by SSYTRF.
[out]WORK
          WORK is REAL array, dimension (N+NNB+1,NNB+3)
[in]NB
          NB is INTEGER
          Block size
[out]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 121 of file ssytri2x.f.

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