DROUNDUP_LWORK.F(3)

💅 NAME 💅

INSTALL/droundup_lwork.f — that's the page title, bestie, and the manual name is Library Functions Manual. Today's main character is the droundup_lwork function, and yes, we're getting into the floating-point tea. 🫶

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🌈 SYNOPSIS 🌈

It's giving Functions/Subroutines energy:

double precision function droundup_lwork (lwork)
    DROUNDUP_LWORK

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🧚 Function/Subroutine Documentation 🧚

The signature, exactly as the docs serve it:

double precision function droundup_lwork (integer lwork)
    DROUNDUP_LWORK

🎯 Purpose 🎯

okay so DROUNDUP_LWORK deals with a subtle bug with returning LWORK as a Float. This routine guarantees it is rounded up instead of down by multiplying LWORK by 1+eps when it is necessary, where eps is the relative machine precision. Iconic behavior, honestly. ✨

E.g., the examples are literally:

float( 9007199254740993            ) == 9007199254740992
float( 9007199254740993 ) * (1.+eps) == 9007199254740994

The return is DROUNDUP_LWORK — like, the docs say \return DROUNDUP_LWORK, and the verbatim block is:

DROUNDUP_LWORK >= LWORK.
DROUNDUP_LWORK is guaranteed to have zero decimal part.

No cap, that's the whole rounding-up vibe. 💖

🎀 Parameters 🎀

• LWORK — Workspace size. That's the parameter, bestie. 🌸

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💖 Author 💖

Shoutout to Weslley Pereira, University of Colorado Denver, USA — that's the author, periodt. 👑

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🦋 Further Details 🦋

This routine was inspired in the method magma_zmake_lwork from MAGMA. The docs also \see this link:

https://bitbucket.org/icl/magma/src/master/control/magma_zauxiliary.cpp

Definition at line 58 of file droundup_lwork.f.

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🫶 Author (Doxygen edition) 🫶

Generated automatically by Doxygen for LAPACK from the source code. Not me, bestie — Doxygen said it. 💅

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Cute sign-off: source/version is LAPACK Version 3.12.0, page tag is INSTALL/droundup_lwork.f(3), and no date is printed on this footer — so that's the whole tea. 🍓🧚💜