lamch(3)

📦
version 3.12.1 · 9 versions
, in arch rolling

okay so bestie, welcome to lamch(3) from the Library Functions Manual — the LAPACK page for machine parameters, and yes it's giving "tiny but important" 🌸. We're gonna walk through every flag, value, and author credit without losing a single crumb. 💖

🌸 NAME 🌸

lamch - lamch: machine parameters

✨ SYNOPSIS ✨

🦋 Functions 🦋

double precision function dlamch (cmach)
    DLAMCH
real function slamch (cmach)
    SLAMCH

💖 Detailed Description 💖

This is the detailed description section, and it's lowkey just the runway before the function docs below. The real tea is in Function Documentation, so let's go. 💅

🎀 Function Documentation 🎀

💅 double precision function dlamch (character cmach) — DLAMCH 💅

Purpose: DLAMCH determines double precision machine parameters. Periodt. ✨

Parameters

  • CMACH — it's a CHARACTER*1. Specifies the value to be returned by DLAMCH:
    • = 'E' or 'e', DLAMCH := eps
    • = 'S' or 's , DLAMCH := sfmin
    • = 'B' or 'b', DLAMCH := base
    • = 'P' or 'p', DLAMCH := eps*base
    • = 'N' or 'n', DLAMCH := t
    • = 'R' or 'r', DLAMCH := rnd
    • = 'M' or 'm', DLAMCH := emin
    • = 'U' or 'u', DLAMCH := rmin
    • = 'L' or 'l', DLAMCH := emax
    • = 'O' or 'o', DLAMCH := 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 68 of file dlamch.f.

🦋 real function slamch (character cmach) — SLAMCH 🦋

Purpose: SLAMCH determines single precision machine parameters. No cap. ✨

Parameters

  • CMACH — it's a CHARACTER*1. 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.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

mwah 💋 that's the whole page, bestie. Final sign-off: LAPACK Version 3.12.0 lamch(3) 💖

📦 where this page comes from