/home/abui...t01_rook.f(3)

🦋 /home/abui...t01_rook.f(3) 🦋

okay bestie, this page is straight out of the Library Functions Manual and it's all about one little Fortran file. No cap, the whole glow-up is here. ✨

---

✨ NAME ✨

It's literally this path, bestie:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/chet01_rook.f

That's the name. That's the whole NAME section. Periodt. 💅

---

🦋 SYNOPSIS 🦋

🧚 Functions/Subroutines

   Functions/Subroutines
       subroutine CHET01_ROOK (uplo, n, a, lda, afac, ldafac, ipiv, c, ldc,
           rwork, resid)
           CHET01_ROOK

---

💅 Function/Subroutine Documentation 💅

Here's the signature in all its exact, character-for-character glory:

   subroutine CHET01_ROOK (character uplo, integer n, complex, dimension( lda,
       * ) a, integer lda, complex, dimension( ldafac, * ) afac, integer
       ldafac, integer, dimension( * ) ipiv, complex, dimension( ldc, * ) c,
       integer ldc, real, dimension( * ) rwork, real resid)
       CHET01_ROOK

---

🌸 Purpose 🌸

So CHET01_ROOK reconstructs a complex Hermitian indefinite matrix A from its block L*D*L' or U*D*U' factorization, and then it computes the residual:

norm( C - A ) / ( N * norm(A) * EPS )

where C is the reconstructed matrix, EPS is the machine epsilon, L' is the transpose of L, and U' is the transpose of U. That's the whole tea. 🫶

---

🎀 Parameters 🎀

🌟 UPLO

UPLO is CHARACTER*1. It specifies whether the upper or lower triangular part of the complex Hermitian matrix A is stored:

• = 'U': Upper triangular
• = 'L': Lower triangular

🌟 N

N is INTEGER. It's the number of rows and columns of the matrix A. And bestie, N >= 0. 💖

🌟 A

A is COMPLEX array, dimension (LDA,N). It's the original complex Hermitian matrix A. iconic.

🌟 LDA

LDA is INTEGER. It's the leading dimension of the array A. Also: LDA >= max(1,N). No skipping that check. 👑

🌟 AFAC

AFAC is COMPLEX array, dimension (LDAFAC,N). It's the factored form of the matrix A. AFAC contains the block diagonal matrix D and the multipliers used to obtain the factor L or U from the block L*D*L' or U*D*U' factorization as computed by CSYTRF_ROOK. fr fr. 🦋

🌟 LDAFAC

LDAFAC is INTEGER. It's the leading dimension of the array AFAC. And yes: LDAFAC >= max(1,N). 🎀

🌟 IPIV

IPIV is INTEGER array, dimension (N). These are the pivot indices from CSYTRF_ROOK. periodt. 💅

🌟 C

C is COMPLEX array, dimension (LDC,N). That's the description. Short and mysterious. main character energy. 🌈

🌟 LDC

LDC is INTEGER. It's the leading dimension of the array C. Also LDC >= max(1,N). You already know. ✨

🌟 RWORK

RWORK is REAL array, dimension (N). That's it. That's the vibe. 🍓

🌟 RESID

RESID is REAL. Here's the exact breakdown:

If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS )
If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS )

So yes, the formula depends on UPLO. slay. 🔥

---

👑 Author

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

Definition at line 123 of file chet01_rook.f. 🎀

---

🌈 Author 🌈

This page was Generated automatically by Doxygen for LAPACK from the source code. So it's not a handwritten love letter, it's a generated one. still iconic. 💜

---

mwah 💋 — cute little sign-off time: the footer says LAPACK Version 3.12.0 and the page path is /home/abui...t01_rook.f(3). That's the whole footer, bestie. 🫶✨