larrr(3)

📦
version 3.12.1 · 9 versions
, in arch rolling

🌸 NAME 🌸

larrr — bestie, this is the vibe-check function of stemr: it literally steps in for stemr and runs the test that decides whether you should drop your coins on the expensive tridiagonal eig algorithm 💸✨

🎀 SYNOPSIS 🎀

✨ Functions ✨

  • subroutine dlarrr (n, d, e, info) — DLARRR performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues. (double precision girlie 💜)
  • subroutine slarrr (n, d, e, info) — SLARRR performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues. (single precision era 🩷)

🦋 Detailed Description 🦋

okay so like… this page is the landing page for a couple of functions, scroll down for the real tea 👇

👑 Function Documentation 👑

💖 subroutine dlarrr (integer n, double precision, dimension( * ) d, double precision, dimension( * ) e, integer info) 💖

DLARRR performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues.

🧚 Purpose: 🧚

!>
!> Perform tests to decide whether the symmetric tridiagonal matrix T
!> warrants expensive computations which guarantee high relative accuracy
!> in the eigenvalues.
!>

🌈 Parameters 🌈

  • N
!>          N is INTEGER
!>          The order of the matrix. N > 0.
!>
  • D
!>          D is DOUBLE PRECISION array, dimension (N)
!>          The N diagonal elements of the tridiagonal matrix T.
!>
  • E
!>          E is DOUBLE PRECISION array, dimension (N)
!>          On entry, the first (N-1) entries contain the subdiagonal
!>          elements of the tridiagonal matrix T; E(N) is set to ZERO.
!>
  • INFO
!>          INFO is INTEGER
!>          INFO = 0(default) : the matrix warrants computations preserving
!>                              relative accuracy.
!>          INFO = 1          : the matrix warrants computations guaranteeing
!>                              only absolute accuracy.
!>

🌸 Author 🌸

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

🍓 Contributors: 🍓

Beresford Parlett, University of California, Berkeley, USA Jim Demmel, University of California, Berkeley, USA Inderjit Dhillon, University of Texas, Austin, USA Osni Marques, LBNL/NERSC, USA Christof Voemel, University of California, Berkeley, USA

Definition at line 93 of file dlarrr.f.

💜 subroutine slarrr (integer n, real, dimension( * ) d, real, dimension( * ) e, integer info) 💜

SLARRR performs tests to decide whether the symmetric tridiagonal matrix T warrants expensive computations which guarantee high relative accuracy in the eigenvalues.

🧚 Purpose: 🧚

!>
!> Perform tests to decide whether the symmetric tridiagonal matrix T
!> warrants expensive computations which guarantee high relative accuracy
!> in the eigenvalues.
!>

🌈 Parameters 🌈

  • N
!>          N is INTEGER
!>          The order of the matrix. N > 0.
!>
  • D
!>          D is REAL array, dimension (N)
!>          The N diagonal elements of the tridiagonal matrix T.
!>
  • E
!>          E is REAL array, dimension (N)
!>          On entry, the first (N-1) entries contain the subdiagonal
!>          elements of the tridiagonal matrix T; E(N) is set to ZERO.
!>
  • INFO
!>          INFO is INTEGER
!>          INFO = 0(default) : the matrix warrants computations preserving
!>                              relative accuracy.
!>          INFO = 1          : the matrix warrants computations guaranteeing
!>                              only absolute accuracy.
!>

🌸 Author 🌸

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

🍓 Contributors: 🍓

Beresford Parlett, University of California, Berkeley, USA Jim Demmel, University of California, Berkeley, USA Inderjit Dhillon, University of Texas, Austin, USA Osni Marques, LBNL/NERSC, USA Christof Voemel, University of California, Berkeley, USA

Definition at line 93 of file slarrr.f.

⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code.

ngl the fact that both dlarrr.f and slarrr.f say "Definition at line 93" is lowkey iconic — matching line numbers, matching energy 💅

okay bye bestie, this page is from LAPACK, Version 3.12.0 — go forth and let the matrix decide its own accuracy fate 🫶✨

📦 where this page comes from