ZPPT01(3)

📦 version 3.12.0, in opensuse-leap 16.0

💖 ZPPT01(3) — Library Functions Manual 💖

okay bestie, welcome to the ZPPT01(3) page from the Library Functions Manual. It lives at /home/abui...IN/zppt01.f(3) and it is very LAPACK-core. 💅

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/zppt01.f

That path is literally the NAME. Iconic, honestly.

✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

subroutine ZPPT01 (uplo, n, a, afac, rwork, resid)
    ZPPT01

💅 Function/Subroutine Documentation 💅

subroutine ZPPT01 (character uplo, integer n, complex*16, dimension( * ) a,
    complex*16, dimension( * ) afac, double precision, dimension( * ) rwork,
    double precision resid)
    ZPPT01

🎀 Purpose 🎀

ZPPT01 reconstructs a Hermitian positive definite packed matrix A from its L*L' or U'*U factorization, then computes the residual:

norm( L*L' - A ) / ( N * norm(A) * EPS )

or

norm( U'*U - A ) / ( N * norm(A) * EPS ),

where EPS is the machine epsilon, L' is the conjugate transpose of L, and U' is the conjugate transpose of U. slay. ✨

🌈 Parameters 🌈

💜 UPLO

UPLO is CHARACTER*1. It specifies whether the upper or lower triangular part of the 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. N >= 0.

🦋 A

A is COMPLEX*16 array, dimension (N*(N+1)/2). It’s the original Hermitian matrix A, stored as a packed triangular matrix.

🎀 AFAC

AFAC is COMPLEX*16 array, dimension (N*(N+1)/2). On entry, it holds the factor L or U from the L*L' or U'*U factorization of A, stored as a packed triangular matrix. It gets overwritten with the reconstructed matrix, and then with the difference L*L' - A (or U'*U - A).

🌸 RWORK

RWORK is DOUBLE PRECISION array, dimension (N).

⭐ RESID

RESID is DOUBLE PRECISION. If UPLO = 'L', it’s norm(L*L' - A) / ( N * norm(A) * EPS ). If UPLO = 'U', it’s norm(U'*U - A) / ( N * norm(A) * EPS ).

🌟 Author 🌟

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

Definition at line 94 of file zppt01.f.

🫶 Author 🫶

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💌 cute little sign-off: this page is from LAPACK, Version 3.12.0, with footer path /home/abui...IN/zppt01.f(3). No date printed on the page, so don’t @ me. periodt. 🎀

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