BLAS/SRC/idamax.f(3)

📦
version 3.12.0 · 7 versions
, in centos-stream 10, fedora 43, fedora 44

💖 BLAS/SRC/idamax.f — the LAPACK manual, but make it cute 💖

okay bestie, gather round, we're reading a LAPACK manpage together and honestly? it's giving iconic. this one lives in the BLAS folder, file name idamax.f, and it's the whole reason your vector knows which element is the drama queen 👑

✨ NAME ✨

BLAS/SRC/idamax.f — no cap, that's the whole name, that's the file, that's the moment 💅

🌸 SYNOPSIS 🌸

Functions/Subroutines

integer function idamax (n, dx, incx)

IDAMAX — that's her. that's the function. she's an integer function and she's about to tell you where the biggest absolute value is living 🦋

💜 Function/Subroutine Documentation 💜

integer function idamax (integer n, double precision, dimension(*) dx,
    integer incx)

IDAMAX

🎀 Purpose:

IDAMAX finds the index of the first element having maximum absolute value.

periodt. she doesn't care about the sign, she doesn't care about the vibe of the number, she cares about the absolute value — and if there's a tie she points at the first one, because she's loyal like that 🫶

⭐ Parameters ⭐

  • N — N is INTEGER, the number of elements in your input vector(s). it's the headcount, the guest list, how many besties showed up to the function 💖
  • DX — DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) ). yes bestie, that dimension expression is a whole mood, but it's just the actual size your array needs to be given how you're striding through it 😭
  • INCX — INCX is INTEGER, the storage spacing between elements of DX. think of it like "how many seats apart are we sitting" — 1 means everyone's cosy and adjacent, bigger numbers mean we're spread out across the room 🧚

👑 Author

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

the whole squad, the founding mothers and fathers of this numerical empire, we love them, we thank them 💜

🔥 Further Details:

jack dongarra, linpack, 3/11/78.
modified 3/93 to return if incx .le. 0.
modified 12/3/93, array(1) declarations changed to array(*)

ngl the lore is deep — jack dongarra, linpack, dated 3/11/78, that's ancient history in the best way. then in 3/93 she got modified to return if incx .le. 0 (translation: if INCX is zero or negative, she just bails and returns, no crash, no drama 🙈). then on 12/3/93 the array(1) declarations got changed to array(*) — glow-up of the century honestly ✨

heads up bestie: INCX being <= 0 means IDAMAX returns early instead of doing the search. that's not a bug, that's the documented behaviour, no cap.

📍 Definition

Definition at line 70 of file idamax.f. — go look, she's right there on line 70 🎀

🌈 Author

Generated automatically by Doxygen for LAPACK from the source code. — so like, a robot wrote this manpage, and a human is now explaining it to you with butterflies. teamwork 💖

okay that's the whole page!! and for the cute lil sign-off: this beauty is from Version 3.12.0, dated Tue Nov 28 2023 12:08:41, filed under BLAS/SRC/idamax.f(3). she ate and left no crumbs 💅✨🦋

📦 where this page comes from