BLAS/SRC/cgemv.f(3)

💖 BLAS/SRC/cgemv.f 💖

okay bestie, welcome to the LAPACK section of the BLAS files — this one is literally called BLAS/SRC/cgemv.f and she is iconic. sit down, grab a strawberry 🍓, and let's get into it.

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✨ SYNOPSIS ✨

🫶 Functions/Subroutines

• subroutine cgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy) — CGEMV, the main character 👑

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💅 Function/Subroutine Documentation 💅

🌸 subroutine cgemv (character trans, integer m, integer n, complex alpha, complex, dimension(lda,*) a, integer lda, complex, dimension(*) x, integer incx, complex beta, complex, dimension(*) y, integer incy)

CGEMV 🦋

🎀 Purpose:

CGEMV performs one of the matrix-vector operations

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

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

where alpha and beta are scalars, x and y are vectors and A is an m by n matrix. no cap, that's the whole vibe. ✨

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💜 Parameters

• TRANS

TRANS is CHARACTER*1. On entry, TRANS specifies the operation to be performed as follows:

TRANS = 'N' or 'n'   y := alpha*A*x + beta*y.

TRANS = 'T' or 't'   y := alpha*A**T*x + beta*y.

TRANS = 'C' or 'c'   y := alpha*A**H*x + beta*y.

lowercase works too, she's not picky, she just wants to know the vibe 💖

• M

M is INTEGER. On entry, M specifies the number of rows of the matrix A. M must be at least zero. 🫶

• N

N is INTEGER. On entry, N specifies the number of columns of the matrix A. N must be at least zero. 🫶

• ALPHA

ALPHA is COMPLEX. On entry, ALPHA specifies the scalar alpha. just a lil scalar bestie 🎀

• A

A is COMPLEX array, dimension ( LDA, N ). Before entry, the leading m by n part of the array A must contain the matrix of coefficients. 👑

• 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, m ). ⭐

• X

X is COMPLEX array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x. 🦋

• INCX

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

literally do not pass zero here, that's the one thing she will not tolerate 💀

• 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. 😌

• Y

Y is COMPLEX array, dimension at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry with BETA non-zero, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. 🔥 If either m or n is zero, then Y not referenced and the function performs a quick return. 🏃‍♀️

not me getting a whole free quick return just because m or n is zero 😭 slay

• INCY

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

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👑 Author

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

the whole squad came together for this one, fr fr 🫶

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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.

1986?? vintage. archival. the blueprint. and yet she still eats every single time 💅

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🧚 Definition at line 159 of file cgemv.f.

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💖 Author

Generated automatically by Doxygen for LAPACK from the source code.

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okay bestie that's the whole page, you ate that, go call cgemv and make her proud 🌸🦋✨

Version 3.12.0 — Tue Nov 28 2023 12:08:41 — BLAS/SRC/cgemv.f(3) 💜 periodt.