SRC/zhetrs_rook.f(3)

🎀 NAME 🎀

SRC/zhetrs_rook.f

okay so bestie, this is the page from the Library Functions Manual for SRC/zhetrs_rook.f(3) — yes, the filename is the whole name, she’s lowkey iconic like that. 💅

---

✨ SYNOPSIS ✨

🌸 Functions/Subroutines 🌸

• zhetrs_rook — the subroutine in question. Short signature first, because that’s how she enters:

subroutine zhetrs_rook (uplo, n, nrhs, a, lda, ipiv, b, ldb, info)

ZHETRS_ROOK computes the solution to a system of linear equations A * X = B for HE matrices using factorization obtained with one of the bounded diagonal pivoting methods (max 2 interchanges). No cap, that’s the whole assignment. 🔥

---

📚 Function/Subroutine Documentation 📚

subroutine zhetrs_rook (character uplo, integer n, integer nrhs, complex*16, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, complex*16, dimension( ldb, * ) b, integer ldb, integer info)

ZHETRS_ROOK computes the solution to a system of linear equations A * X = B for HE matrices using factorization obtained with one of the bounded diagonal pivoting methods (max 2 interchanges).

💡 Purpose 💡

ZHETRS_ROOK solves a system of linear equations A*X = B with a complex Hermitian matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by ZHETRF_ROOK.

That’s the vibe: it’s the solve step after the factorization has already done its thing. 🫶

🧚 Parameters 🧚

• UPLO — UPLO is CHARACTER*1. Tells you 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. The order of the matrix A. Must be N >= 0.
• NRHS — NRHS is INTEGER. The number of right hand sides, i.e., the number of columns of the matrix B. Must be NRHS >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZHETRF_ROOK.
• LDA — LDA is INTEGER. The leading dimension of the array A. Must be LDA >= max(1,N).
• IPIV — IPIV is INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by ZHETRF_ROOK.
• B — B is COMPLEX*16 array, dimension (LDB,NRHS). On entry, the right hand side matrix B. On exit, the solution matrix X. Literally the glow-up happens here. ✨
• LDB — LDB is INTEGER. The leading dimension of the array B. Must be LDB >= max(1,N).
• INFO — INFO is INTEGER. = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value.

bestie if INFO < 0, that’s not a vibe — it means an argument was illegal, specifically the i-th one when INFO = -i. Fix it before you come for the matrix. 💀

🫶 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 134 of file zhetrs_rook.f.

That’s the exact line, no need to squint. 👑

📜 Author 📜

Generated automatically by Doxygen for LAPACK from the source code.

---

LAPACK Version 3.12.0, source SRC/zhetrs_rook.f(3) — and the date tea on this page comes from the contributors above: November 2013 and September 2007. bye bestie, go solve that Hermitian system responsibly! 💖✨🎀