ZHEMV(3)

💖 ZHEMV(3) — the zhemv.f page from the Library Functions Manual ✨

okay so bestie, before anything else: this whole page lives at /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/zhemv.f — like, that's the file, that's the whole vibe, that's the address 💅

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🦋 SYNOPSIS

Functions/Subroutines

• subroutine ZHEMV (uplo, n, alpha, a, lda, x, incx, beta, y, incy) — the one, the only, ZHEMV 👑

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🌸 Function/Subroutine Documentation

subroutine ZHEMV (character uplo, integer n, complex*16 alpha, complex*16,
    dimension(lda,*) a, integer lda, complex*16, dimension(*) x, integer
    incx, complex*16 beta, complex*16, dimension(*) y, integer incy)

ZHEMV 💫

🎀 Purpose:

!>
!> ZHEMV  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.
!>

literally that's it, that's the whole math. hermitian matrix A, vectors x and y, scalars alpha and beta, and the girlies get multiplied. slay 🫶

✨ Parameters

• UPLO — UPLO is CHARACTER*1. on entry, UPLO specifies whether the upper or lower triangular part of the array A is to be referenced, like so:

!>              UPLO = 'U' or 'u'   Only the upper triangular part of A
!>                                  is to be referenced.
!>
!>              UPLO = 'L' or 'l'   Only the lower triangular part of A
!>                                  is to be referenced.

so 'U'/'u' = upper only, 'L'/'l' = lower only. pick your fighter 💅

• N — N is INTEGER. on entry, N specifies the order of the matrix A. and N must be at least zero. no negatives bestie, we don't do that here 🙈
• ALPHA — ALPHA is COMPLEX*16. on entry, ALPHA specifies the scalar alpha. that's the whole job. iconic honestly.
• A — A is COMPLEX*16 array, dimension ( LDA, N ). before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must contain the upper triangular part of the hermitian matrix, and the strictly lower triangular part of A is not referenced. before entry with UPLO = 'L' or 'l', the leading n by n lower triangular part of the array A must contain the lower triangular part of the hermitian matrix, and the strictly upper triangular part of A is not referenced. note that the imaginary parts of the diagonal elements need not be set and are assumed to be zero 🧚 — yes, assumed, so don't come for her if you left them lying around 💀
• LDA — LDA is INTEGER. on entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, n ). that's the floor, bestie, no going below it ⭐
• X — X is COMPLEX*16 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. zero is not the move, fr fr 🔥
• BETA — BETA is COMPLEX*16. on entry, BETA specifies the scalar beta. when BETA is supplied as zero then Y need not be set on input 🫶 — free pass, use it wisely.
• Y — Y is COMPLEX*16 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 😭 she gets a whole new personality, that's main character energy.
• INCY — INCY is INTEGER. on entry, INCY specifies the increment for the elements of Y. INCY must not be zero. same rule as INCX, we stay consistent 💜

👑 Author

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

the whole squad showed up, we love a collaborative era 🌈

💀 Further Details:

!>
!>  Level 2 Blas routine.
!>  The vector and matrix arguments are not referenced when N = 0, or M = 0
!>
!>  -- 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, bestie. and note the caveat in there: the vector and matrix arguments are not referenced when N = 0, or M = 0 — so like, zero-size and nobody gets touched, no cap 🙈

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). literal legends, older than the internet, still serving 💅

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Definition at line 153 of file zhemv.f. 📍

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🍓 Sign-off

this page was generated automatically by Doxygen for LAPACK from the source code, so like, a robot wrote the original — but I rewrote it for you 💖 and it's from LAPACK, Version 3.12.0, living at /home/abui...SRC/zhemv.f(3) 🎀 ok bye, go call ZHEMV, she's waiting ✨🦋