dgetri.f(3)

NAME
dgetri.f -

SYNOPSIS

  Functions/Subroutines
subroutine dgetri (N, A, LDA, IPIV, WORK, LWORK, INFO)
DGETRI

Function/Subroutine Documentation

  subroutine dgetri (integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, double precision, dimension( * )WORK, integerLWORK, integerINFO)

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.

Date:
    November 2011

Definition at line 115 of file dgetri.f.

Author

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