# dsytri2.f(3) [debian man page]

dsytri2.f(3) LAPACK dsytri2.f(3)NAME

dsytri2.f-SYNOPSIS

Functions/Subroutines subroutine dsytri2 (UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO) DSYTRI2Function/Subroutine Documentation subroutine dsytri2 (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, double precision, dimension( * )WORK, integerLWORK, integerINFO) DSYTRI2 Purpose: DSYTRI2 computes the inverse of a DOUBLE PRECISION hermitian 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 =, 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 =-1, 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 128 of file dsytri2.f.-iAuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.1Sun May 26 2013 dsytri2.f(3)

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dsytri2x.f(3) LAPACK dsytri2x.f(3)NAME

dsytri2x.f-SYNOPSIS

Functions/Subroutines subroutine dsytri2x (UPLO, N, A, LDA, IPIV, WORK, NB, INFO) DSYTRI2XFunction/Subroutine Documentation subroutine dsytri2x (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, double precision, dimension( n+nb+1,* )WORK, integerNB, integerINFO) 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+NNB+1,NNB+3) NB NB is INTEGER Block size INFO INFO is INTEGER = 0: successful exit < 0: if INFO =, 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 dsytri2x.f.-iAuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.2Tue Sep 25 2012 dsytri2x.f(3)