SRC/srscl.f(3)

📦
version 3.12.1 · 4 versions
, in arch rolling

💅 SRC/srscl.f

okay so this is a page from the LAPACK manual — Library Functions Manual, if we're being fancy — and it's all about one lil subroutine that rescales a vector without everything exploding into overflow. it's giving "tiny but powerful" energy fr fr 🫶

✨ SYNOPSIS ✨

🌈 Functions/Subroutines

  • subroutine srscl (n, sa, sx, incx) — SRSCL multiplies a vector by the reciprocal of a real scalar.

🎀 Function/Subroutine Documentation 🎀

subroutine srscl (integer n, real sa, real, dimension( * ) sx, integer incx)

SRSCL multiplies a vector by the reciprocal of a real scalar. that's the whole vibe, bestie 💖

🌸 Purpose:

!>
!> SRSCL multiplies an n-element real vector x by the real scalar 1/a.
!> This is done without overflow or underflow as long as
!> the final result x/a does not overflow or underflow.
!>

so like — it divides your whole vector by a, but it's smart about it. no overflow, no underflow, as long as the final answer x/a itself fits in range. that caveat is doing a lot of work, so don't sleep on it 👀

🦋 Parameters

  • N — N is INTEGER. the number of components of the vector x. lowkey just "how long is your vector" 💅
  • SA — SA is REAL. the scalar a which is used to divide each component of x. SA must be >= 0, or the subroutine will divide by zero. 🚨 like, that's not a suggestion, that's a hard requirement — ignore it and you get a divide-by-zero situation, no cap.
  • SX — SX is REAL array, dimension (1+(N-1)*abs(INCX)). the n-element vector x. yes the dimension expression is that whole thing, write it down exactly, don't get creative ✨
  • INCX — INCX is INTEGER. the increment between successive values of the vector SX. and then the spec drops this:
> 0:  SX(1) = X(1) and SX(1+(i-1)*INCX) = x(i),     1< i<= n

iykyk — that's the stride math, and it's precise, so respect it 🧚

👑

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

the whole squad contributed, iconic behavior honestly 💜

Definition at line 83 of file srscl.f.

⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code. (so if the formatting's a little quirky, blame the robot, not me 🙈)

💀 real talk reminder: SA must be >= 0 — the page says it twice-ish, so i'm saying it too. divide-by-zero is not the cute kind of chaos.

LAPACK — Version 3.12.0 🦋 and that's the page, bestie — SRC/srscl.f(3), signed, sealed, slayed. mwah 💋🎀

📦 where this page comes from