TESTING/LIN/chpt01.f(3)

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💖 TESTING/LIN/chpt01.f(3) — Library Functions Manual 💖

okay bestie, welcome to TESTING/LIN/chpt01.f(3) from the Library Functions Manual 💅 this one is giving “LAPACK test routine that checks its own work,” and honestly? iconic.

🌸 NAME 🌸

TESTING/LIN/chpt01.f

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine chpt01 (uplo, n, a, afac, ipiv, c, ldc, rwork, resid)
CHPT01

🫶 Function/Subroutine Documentation 🫶

   subroutine chpt01 (character uplo, integer n, complex, dimension( * ) a,
       complex, dimension( * ) afac, integer, dimension( * ) ipiv, complex,
       dimension( ldc, * ) c, integer ldc, real, dimension( * ) rwork, real
       resid)

CHPT01 — she’s the main character here, no cap.

🎯 Purpose

CHPT01 reconstructs a Hermitian indefinite packed matrix A from its block L*D*L' or U*D*U' factorization, then computes the residual

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

where C is the reconstructed matrix, EPS is the machine epsilon, L' is the conjugate transpose of L, and U' is the conjugate transpose of U. literally the whole vibe: rebuild, then check the damage 💖

🌈 Parameters

  • UPLO — UPLO is CHARACTER*1. It says whether the upper or lower triangular part of the Hermitian matrix A is stored: = 'U': Upper triangular; = 'L': Lower triangular. choose your fighter 🎀
  • N — N is INTEGER. It’s the number of rows and columns of the matrix A. N >= 0.
  • A — A is COMPLEX array, dimension (N*(N+1)/2). It’s the original Hermitian matrix A, stored as a packed triangular matrix. the original before all the factorization chaos ✨
  • AFAC — AFAC is COMPLEX array, dimension (N*(N+1)/2). It’s the factored form of the matrix A, stored as a packed triangular matrix. 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 CHPTRF. yes ma’am, that’s a lot of letters and every one matters 💅
  • IPIV — IPIV is INTEGER array, dimension (N). These are the pivot indices from CHPTRF.
  • C — C is COMPLEX array, dimension (LDC,N).
  • LDC — LDC is INTEGER. It’s the leading dimension of the array C. LDC >= max(1,N).
  • RWORK — RWORK is REAL array, dimension (N).
  • RESID — RESID is REAL. If UPLO = 'L', then norm(L*D*L' - A) / ( N * norm(A) * EPS ). If UPLO = 'U', then norm(U*D*U' - A) / ( N * norm(A) * EPS ). the final grade, bestie 🍓

👑 Author

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

Definition at line 112 of file chpt01.f.

💀 Author 💀

Generated automatically by Doxygen for LAPACK from the source code. not a human author, just Doxygen doing its little automation slay 🤖✨

byeee 🫶 this icon is from LAPACK Version 3.12.0, and the file tag is TESTING/LIN/chpt01.f(3) — mwah 🎀💖
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