KTH framework for Nek5000 toolboxes; testing version  0.0.1
Functions/Subroutines
dgetri.f File Reference

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Functions/Subroutines

subroutine dgetri (N, A, LDA, IPIV, WORK, LWORK, INFO)
 DGETRI More...
 

Function/Subroutine Documentation

◆ dgetri()

subroutine dgetri ( integer  N,
double precision, dimension( lda, * )  A,
integer  LDA,
integer, dimension( * )  IPIV,
double precision, dimension( * )  WORK,
integer  LWORK,
integer  INFO 
)

DGETRI

Download DGETRI + dependencies [TGZ] [ZIP] [TXT]

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
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in,out]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.
[in]LDA
          LDA is INTEGER
          The leading dimension of the array A.  LDA >= max(1,N).
[in]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).
[out]WORK
          WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
          On exit, if INFO=0, then WORK(1) returns the optimal LWORK.
[in]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.
[out]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
December 2016

Definition at line 115 of file dgetri.f.

References dgemm(), dgemv(), dswap(), dtrsm(), dtrtri(), and xerbla().

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