SLAMCH(3)

🎀 SLAMC3(3) — Library Functions Manual 🎀

okay bestie, welcome to the SLAMC3(3) page ✨ the header path is /home/abui...LL/slamch.f(3) — yes, that's the vibe. this is LAPACK land, so buckle up 🫶

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💅 NAME 💅

the NAME section is lowkey just this file path, no cap:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/INSTALL/slamch.f

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🌸 SYNOPSIS 🌸

Functions/Subroutines

real function SLAMCH (cmach)
    SLAMCH
real function SLAMC3 (a, b)
    SLAMC3

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🦋 Function/Subroutine Documentation 🦋

⭐ real function SLAMC3 (real a, real b)

SLAMC3 Purpose:

okay so SLAMC3 is intended to force A and B to be stored prior to doing the addition of A and B, for use in situations where optimizers might hold one of these in a register. that's the whole point, periodt 🔥

Author

LAPACK is a software package provided by Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..

Parameters

• A — the source leaves this one with just the Doxygen !> marker, no extra description 🙈
• B — !> The values A and B. and then !> (the values are A and B, bestie) 💖

Purpose:

same energy, second pass ✨ SLAMC3 is intended to force A and B to be stored prior to doing the addition of A and B, for use in situations where optimizers might hold one of these in a register.

Parameters

• A — the source's shared note here is The values A and B. (wrapped in !> markers)
• B — the source's shared note here is The values A and B. (wrapped in !> markers)

Definition at line 170 of file slamch.f.

⭐ real function SLAMCH (character cmach)

SLAMCH SLAMCHF77 deprecated — yes bestie, deprecated, so treat it with legacy respect 💀

Purpose:

SLAMCH determines single precision machine parameters. 💅

Parameters

• CMACH — the source comment says CMACH is CHARACTER*1, and it says: Specifies the value to be returned by SLAMCH:

= 'E' or 'e',   SLAMCH := eps
= 'S' or 's ,   SLAMCH := sfmin
= 'B' or 'b',   SLAMCH := base
= 'P' or 'p',   SLAMCH := eps*base
= 'N' or 'n',   SLAMCH := t
= 'R' or 'r',   SLAMCH := rnd
= 'M' or 'm',   SLAMCH := emin
= 'U' or 'u',   SLAMCH := rmin
= 'L' or 'l',   SLAMCH := emax
= 'O' or 'o',   SLAMCH := rmax

where:

eps   = relative machine precision
sfmin = safe minimum, such that 1/sfmin does not overflow
base  = base of the machine
prec  = eps*base
t     = number of (base) digits in the mantissa
rnd   = 1.0 when rounding occurs in addition, 0.0 otherwise
emin  = minimum exponent before (gradual) underflow
rmin  = underflow threshold - base**(emin-1)
emax  = largest exponent before overflow
rmax  = overflow threshold  - (base**emax)*(1-eps)

Author

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

Purpose:

SLAMCH determines single precision machine parameters. yes, again — the source said it twice and we're not skipping anything 🫶

Parameters

• CMACH — Specifies the value to be returned by SLAMCH:

= 'E' or 'e',   SLAMCH := eps
= 'S' or 's ,   SLAMCH := sfmin
= 'B' or 'b',   SLAMCH := base
= 'P' or 'p',   SLAMCH := eps*base
= 'N' or 'n',   SLAMCH := t
= 'R' or 'r',   SLAMCH := rnd
= 'M' or 'm',   SLAMCH := emin
= 'U' or 'u',   SLAMCH := rmin
= 'L' or 'l',   SLAMCH := emax
= 'O' or 'o',   SLAMCH := rmax

where:

eps   = relative machine precision
sfmin = safe minimum, such that 1/sfmin does not overflow
base  = base of the machine
prec  = eps*base
t     = number of (base) digits in the mantissa
rnd   = 1.0 when rounding occurs in addition, 0.0 otherwise
emin  = minimum exponent before (gradual) underflow
rmin  = underflow threshold - base**(emin-1)
emax  = largest exponent before overflow
rmax  = overflow threshold  - (base**emax)*(1-eps)

Author

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

Definition at line 67 of file slamch.f.

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🎀 Author 🎀

Generated automatically by Doxygen for LAPACK from the source code.

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xoxo, your LAPACK bestie 💖 — LAPACK, Version 3.12.0, page path /home/abui...LL/slamch.f(3). slay and stay safe 🦋