CHEMV(3)

💖 CHEMV(3) — like, the BLAS hermitian matrix-vector girlie 💖

okay bestie, so this page lives at /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/chemv.f and it's from the Library Functions Manual — it's giving "chemv.f(3)" energy and honestly? iconic. come sit with me, we're gonna read it together 🫶

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✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/chemv.f — yes that's the whole name, she's a long one, no cap 😭

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🌸 SYNOPSIS 🌸

Functions/Subroutines

subroutine CHEMV (uplo, n, alpha, a, lda, x, incx, beta, y, incy)
    CHEMV

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🦋 Function/Subroutine Documentation 🦋

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

💜 Purpose:

!> !> CHEMV 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. !>

so basically she does the matrix-vector thing, 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. main character math fr fr 🔥

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🎀 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 as !> follows: !> !> 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. !>

she's a CHARACTER*1 and on entry she tells you which triangle of A we're looking at — 'U'/'u' means only the upper triangular part of A gets referenced, 'L'/'l' means only the lower triangular part. pick your fighter 💅

N

!> N is INTEGER !> On entry, N specifies the order of the matrix A. !> N must be at least zero. !>

INTEGER. on entry, N specifies the order of the matrix A, and she must be at least zero. respect the boundary 🙏

ALPHA

!> ALPHA is COMPLEX !> On entry, ALPHA specifies the scalar alpha. !>

COMPLEX, and on entry she specifies the scalar alpha. that's it, that's her whole job ✨

A

!> A is COMPLEX 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. !>

COMPLEX 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. so don't stress about them, bestie 🍓

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 ). !>

INTEGER. on entry, LDA specifies the first dimension of A as declared in the calling (sub) program, and LDA must be at least max( 1, n ). lowkey important 🔑

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. !>

COMPLEX array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). before entry, the incremented array X must contain the n element vector x. she's ready to go 💫

INCX

!> INCX is INTEGER !> On entry, INCX specifies the increment for the elements of !> X. INCX must not be zero. !>

INTEGER. on entry, INCX specifies the increment for the elements of X, and INCX must not be zero. like, at all. zero is not the vibe 💀

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. !>

COMPLEX. on entry, BETA specifies the scalar beta. and here's the lil shortcut: when BETA is supplied as zero, then Y need not be set on input. free pass, slay 🎀

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. !>

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 — so yeah, she does not survive the visit, that's the whole point 🙈

INCY

!> INCY is INTEGER !> On entry, INCY specifies the increment for the elements of !> Y. INCY must not be zero. !>

INTEGER. on entry, INCY specifies the increment for the elements of Y. and INCY must not be zero — same rule as her sister, no exceptions 🚫

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👑 Author 👑

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

the whole squad, we stan 🫶

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🌈 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. !>

this is a Level 2 Blas routine. also, the vector and matrix arguments are not referenced when N = 0, or M = 0.

and the receipts, dated 22-October-1986:

• Jack Dongarra, Argonne National Lab.
• Jeremy Du Croz, Nag Central Office.
• Sven Hammarling, Nag Central Office.
• Richard Hanson, Sandia National Labs.

1986?? the way she's been serving since before most of us were born 😭👑

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Definition at line 153 of file chemv.f.

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🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code. a bot wrote this, but the bot understood the assignment, ngl 💅

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okay that's the whole page, you ate that reading session up 💖 this was LAPACK, Version 3.12.0, living at /home/abui...SRC/chemv.f(3) — bye bestie, go call this subroutine, she's waiting ✨🎀