/home/abui...tri_rook.f(3)

💖 NAME 💖

okay so bestie, you're on the /home/abui...tri_rook.f(3) page in the Library Functions Manual — yes, that's the manual name, and yes, we love a straightforward legend. The name this page is serving is:

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

That path is giving “I live deep in the build tree and I know things.” 🦋

---

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

• subroutine CHETRI_ROOK (uplo, n, a, lda, ipiv, work, info) — CHETRI_ROOK computes the inverse of HE matrix using the factorization obtained with the bounded Bunch-Kaufman (rook")diagonalpivotingmethod.

---

🦋 Function/Subroutine Documentation 🦋

👑 subroutine CHETRI_ROOK 👑

   subroutine CHETRI_ROOK (character uplo, integer n, complex, dimension( lda,
       * ) a, integer lda, integer, dimension( * ) ipiv, complex, dimension( *
       ) work, integer info)

This icon right here — CHETRI_ROOK — computes the inverse of HE matrix using the factorization obtained with the bounded Bunch-Kaufman ("rook") diagonal pivoting method. No cap, that's the whole job. 💅

💜 Purpose: 💜

CHETRI_ROOK computes the inverse of a complex Hermitian indefinite matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by CHETRF_ROOK.

That's the main character energy: take the factorization from CHETRF_ROOK, use it to get the inverse, and keep the Hermitian math cute. 🌸

🌸 Parameters 🌸

✨ UPLO ✨

• UPLO is CHARACTER*1.
• It specifies whether the details of the factorization are stored as an upper or lower triangular matrix.
  • = 'U': Upper triangular, form is A = U*D*U**H;
  • = 'L': Lower triangular, form is A = L*D*L**H.

✨ N ✨

• N is INTEGER.
• It's the order of the matrix A. N >= 0.

✨ A ✨

• A is COMPLEX array, dimension (LDA,N).
• On entry, it's the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CHETRF_ROOK.
• On exit, if INFO = 0, it's the (Hermitian) inverse of the original matrix.
• If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced.
• If UPLO = 'L', the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced.

✨ LDA ✨

• LDA is INTEGER.
• It's the leading dimension of the array A. LDA >= max(1,N).

✨ IPIV ✨

• IPIV is INTEGER array, dimension (N).
• It holds the details of the interchanges and the block structure of D as determined by CHETRF_ROOK.

✨ WORK ✨

• WORK is COMPLEX array, dimension (N).
• That's the whole entry, bestie. 🫶

✨ INFO ✨

• INFO is INTEGER.
  • = 0: successful exit.
  • < 0: if INFO = -i, the i-th argument had an illegal value.
  • > 0: if INFO = i, D(i,i) = 0; 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.

---

🌈 Contributors: 🌈

• November 2013, Igor Kozachenko, Computer Science Division, University of California, Berkeley
• September 2007, Sven Hammarling, Nicholas J. Higham, Craig Lucas, School of Mathematics, University of Manchester

Definition at line 127 of file chetri_rook.f.

---

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

---

💖 cute sign-off: this page is LAPACK Version 3.12.0, and the footer path is /home/abui...tri_rook.f(3). That's the whole page, bestie — slay responsibly. 💅✨