SGETRI(3)

πŸ“¦ version 3.12.0, in opensuse-leap 16.0

πŸ’… /home/abui...RC/sgetri.f(3) β€” Library Functions Manual πŸ’…

✨ NAME ✨

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

πŸ¦‹ SYNOPSIS πŸ¦‹

🌈 Functions/Subroutines 🌈

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

πŸ’– Function/Subroutine Documentation πŸ’–

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. πŸ”₯

This method inverts U and then computes inv(A) by solving the system inv(A)*L = inv(U) for inv(A). Slay, honestly. ✨

πŸ“ Parameters πŸ“

πŸŽ€ N

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

πŸŽ€ 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.

πŸŽ€ LDA

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

πŸŽ€ 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).

πŸŽ€ WORK

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

πŸŽ€ 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.

πŸŽ€ 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.
🚨 Warning vibe, bestie: if INFO = i, then U(i,i) is exactly zero, the matrix is singular, and its inverse could not be computed. That is not a slay. That is a wrap. πŸ’€

πŸ‘‘ Author πŸ‘‘

  • Univ. of Tennessee
  • Univ. of California Berkeley
  • Univ. of Colorado Denver
  • NAG Ltd.

πŸ“Œ Definition at line 113 of file sgetri.f.

🧚 Author 🧚

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