CHPMV(3)

✨ NAME ✨

okay so this is /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/chpmv.f, living its best life in the Library Functions Manual 💖 — it's CHPMV, the packed-hermitian matrix-vector girlie, and she's here to do exactly one thing and do it flawlessly ✨

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🦋 SYNOPSIS 🦋

Functions/Subroutines

subroutine CHPMV (uplo, n, alpha, ap, x, incx, beta, y, incy)

CHPMV

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💖 Function/Subroutine Documentation 💖

the full signature, so you can see exactly what you're signing up for 🫶

subroutine CHPMV (character uplo, integer n, complex alpha, complex,
    dimension(*) ap, complex, dimension(*) x, integer incx, complex beta,
    complex, dimension(*) y, integer incy)

CHPMV

🎀 Purpose 🎀

bestie, CHPMV performs the matrix-vector operation

y := alpha*A*x + beta*y,

where alpha and beta are scalars, x and y are n element vectors and A is an n by n hermitian matrix, supplied in packed form. that's the whole vibe 💅

🌸 Parameters 🌸

UPLO

UPLO is CHARACTER*1. on entry, UPLO specifies 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. no negative orders, she doesn't do that 🙈

ALPHA

ALPHA is COMPLEX. on entry, ALPHA specifies the scalar alpha. that's it, that's the whole job 🎀

AP

AP is COMPLEX 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 hermitian 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.

before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular part of the hermitian 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.

note that the imaginary parts of the diagonal elements need not be set and are assumed to be zero 👑 — so don't stress about them, they're handled.

X

X is COMPLEX array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). before entry, the incremented array X must contain the n element vector x. slay 🌈

INCX

INCX is INTEGER. on entry, INCX specifies the increment for the elements of X. INCX must not be zero. fr fr, do not pass zero 💀

BETA

BETA is COMPLEX. on entry, BETA specifies the scalar beta. when BETA is supplied as zero then Y need not be set on input — little treat for you 🍓

Y

Y is COMPLEX array, dimension at least ( 1 + ( n - 1 )*abs( INCY ) ). before entry, the incremented array Y must contain the n element vector y. on exit, Y is overwritten by the updated vector y. main character behaviour, honestly 🔥

INCY

INCY is INTEGER. on entry, INCY specifies the increment for the elements of Y. INCY must not be zero. same rule as INCX, bestie, no zeros 🫶

👑 Author 👑

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

⭐ Further Details ⭐

• Level 2 Blas routine.
• The vector and matrix arguments are not referenced when N = 0, or M = 0. (yes, M — there's no M in this signature, that's just literally how the note reads, iykyk 💀)
• -- 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.

definition at line 148 of file chpmv.f. 📍

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🌈 Author 🌈

generated automatically by Doxygen for LAPACK from the source code. not me, not you, the robot did it 🧚

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and that's the page!! sending you off with the footer energy: LAPACK, Version 3.12.0, /home/abui...SRC/chpmv.f(3) — go forth and pack your hermitian matrices correctly, ily 💜✨