BLAS/SRC/dspr.f(3)

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version 3.12.1 · 4 versions
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💅 BLAS/SRC/dspr.f(3) — Library Functions Manual 🎀

okay bestie, buckle up — this is the man page for BLAS/SRC/dspr.f, straight out of the Library Functions Manual, and honestly? she's iconic. let's get into it ✨

🌸 NAME 🌸

BLAS/SRC/dspr.f — that's the file, that's the vibe, that's the whole name 💖

✨ SYNOPSIS ✨

🦋 Functions/Subroutines

subroutine dspr (uplo, n, alpha, x, incx, ap)

DSPR — literally the main character of this page 👑

🧚 Function/Subroutine Documentation 🧚

subroutine dspr (character uplo, integer n, double precision alpha, double
    precision, dimension(*) x, integer incx, double precision, dimension(*)
    ap)

DSPR

💜 Purpose:

!>
!> DSPR    performs the symmetric rank 1 operation
!>
!>    A := alpha*x*x**T + A,
!>
!> where alpha is a real scalar, x is an n element vector and A is an
!> n by n symmetric matrix, supplied in packed form.
!>

so basically she does a symmetric rank 1 operation, no cap 💅 the formula is right there: A := alpha*x*x**T + A, where alpha is a real scalar, x is an n element vector, and A is an n by n symmetric matrix supplied in packed form. slay.

🎀 Parameters 🎀

  • UPLO — UPLO is CHARACTER*1. on entry, UPLO tells you whether the upper or lower triangular part of the matrix A is supplied in the packed array AP, like this:
    • UPLO = 'U' or 'u' → the upper triangular part of A is supplied in AP.
    • UPLO = 'L' or 'l' → the lower triangular part of A is supplied in AP.
  • N — N is INTEGER. on entry, N specifies the order of the matrix A. N must be at least zero. (zero is allowed, bestie, she's not gonna judge 🫶)
  • ALPHA — ALPHA is DOUBLE PRECISION. on entry, ALPHA specifies the scalar alpha. 🌟
  • X — X is DOUBLE PRECISION array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). before entry, the incremented array X must contain the n element vector x. 💖
  • INCX — INCX is INTEGER. on entry, INCX specifies the increment for the elements of X. INCX must not be zero. ⚠️ like, genuinely not zero. don't do it.
  • AP — AP is DOUBLE PRECISION array, dimension at least ( ( n*( n + 1 ) )/2 ). before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular part of the symmetric matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. on exit, the array AP is overwritten by the upper triangular part of the updated matrix. 💀 before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular part of the symmetric matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. on exit, the array AP is overwritten by the lower triangular part of the updated matrix. 🔥

🌈 Author 🌈

the legends themselves, fr fr:

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

⭐ Further Details:

!>
!>  Level 2 Blas routine.
!>
!>  -- Written on 22-October-1986.
!>     Jack Dongarra, Argonne National Lab.
!>     Jeremy Du Croz, Nag Central Office.
!>     Sven Hammarling, Nag Central Office.
!>     Richard Hanson, Sandia National Labs.
!>

Level 2 Blas routine, written on 22-October-1986 by Jack Dongarra (Argonne National Lab), Jeremy Du Croz (Nag Central Office), Sven Hammarling (Nag Central Office) and Richard Hanson (Sandia National Labs). vintage ✨ we stan an old-school icon.

🍓 Definition 🍓

definition at line 126 of file dspr.f 📍

🫶 Author 🫶

generated automatically by Doxygen for LAPACK from the source code. not a human, but she still ate 💅

ngl bestie, if you're passing INCX = 0 that's on you — the page literally says it must not be zero 🙈

LAPACK — Version 3.12.0 — BLAS/SRC/dspr.f(3)

and that's the whole page, bestie — mwah, go forth and pack those triangular arrays 💖✨🎀🦋🌸💅🫶😭🔥👑🌈⭐💀🙈🍓🧚💜

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