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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/sgetri.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/sgetri.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/sgetri.f

SYNOPSIS

Functions/Subroutines


subroutine SGETRI (n, a, lda, ipiv, work, lwork, info)
SGETRI

Function/Subroutine Documentation

subroutine SGETRI (integer n, real, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, real, dimension( * ) work, integer lwork, integer info)

SGETRI

Purpose:

!>
!> SGETRI computes the inverse of a matrix using the LU factorization
!> computed by SGETRF.
!>
!> 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 REAL array, dimension (LDA,N)
!>          On entry, the factors L and U from the factorization
!>          A = P*L*U as computed by SGETRF.
!>          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 SGETRF; for 1<=i<=N, row i of the
!>          matrix was interchanged with row IPIV(i).
!> 

WORK

!>          WORK is REAL 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 sgetri.f.

Author

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Version 3.12.0 LAPACK