SRC/dgetri.f(3)

NAME
SRC/dgetri.f

SYNOPSIS

  Functions/Subroutines
subroutine dgetri (n, a, lda, ipiv, work, lwork, info)
DGETRI

Function/Subroutine Documentation

  subroutine dgetri (integer n, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision, dimension( * ) work, integer lwork, integer info)

DGETRI

Purpose:

    !>
    !> DGETRI computes the inverse of a matrix using the LU factorization
    !> computed by DGETRF.
    !>
    !> This method inverts U and then computes inv(A) by solving the system
    !> inv(A)*L = inv(U) for inv(A).
    !>

Parameters
    N

    !>          N is INTEGER
    !>          The order of the matrix A.  N >= 0.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA,N)
    !>          On entry, the factors L and U from the factorization
    !>          A = P*L*U as computed by DGETRF.
    !>          On exit, if INFO = 0, the inverse of the original matrix A.
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of the array A.  LDA >= max(1,N).
    !>

    IPIV

    !>          IPIV is INTEGER array, dimension (N)
    !>          The pivot indices from DGETRF; for 1<=i<=N, row i of the
    !>          matrix was interchanged with row IPIV(i).
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
    !>          On exit, if INFO=0, then WORK(1) returns the optimal LWORK.
    !>

    LWORK

    !>          LWORK is INTEGER
    !>          The dimension of the array WORK.  LWORK >= max(1,N).
    !>          For optimal performance LWORK >= N*NB, where NB is
    !>          the optimal blocksize returned by ILAENV.
    !>
    !>          If LWORK = -1, then a workspace query is assumed; the routine
    !>          only 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 LWORK 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, U(i,i) is exactly zero; 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.

Definition at line 113 of file dgetri.f.

Author

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