BLAS/SRC/dsymv.f(3)

💖 NAME 💖

okay so bestie, this is the BLAS/SRC/dsymv.f(3) page from the Library Functions Manual ✨ — the dsymv BLAS routine, in full glow-up form, with every detail still intact. No cap. 💅

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🌸 SYNOPSIS 🌸

🌈 Functions/Subroutines

• subroutine dsymv (uplo, n, alpha, a, lda, x, incx, beta, y, incy) — DSYMV

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👑 Function/Subroutine Documentation 👑

Here’s the main-character signature, exactly as written:

subroutine dsymv (character uplo, integer n, double precision alpha, double precision, dimension(lda,*) a, integer lda, double precision, dimension(*) x, integer incx, double precision beta, double precision, dimension(*) y, integer incy)

DSYMV

🎀 Purpose 🎀

!>
!> DSYMV  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 symmetric matrix.
!>

In human terms: it does that matrix-vector operation up there — y := alpha*A*x + beta*y — with alpha and beta as scalars, x and y as n element vectors, and A as an n by n symmetric matrix. Slay. 💖

💅 Parameters 💅

• UPLO — is CHARACTER*1. On entry, UPLO tells you which triangular part of the array A is to be referenced, like this:
  • 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.
• N — is INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero. Zero is valid, bestie. 🫶
• ALPHA — is DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha.
• A — is a DOUBLE PRECISION array with 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 symmetric 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 symmetric matrix, and the strictly upper triangular part of A is not referenced.
• 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 ).
• X — is a DOUBLE PRECISION array with dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element vector x.
• INCX — is INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.
• BETA — is DOUBLE PRECISION. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input.
• Y — is a DOUBLE PRECISION array with 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.
• INCY — is INTEGER. On entry, INCY specifies the increment for the elements of Y. INCY must not be zero.

🌟 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
• -- 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 151 of file dsymv.f.

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🦋 Author 🦋

Generated automatically by Doxygen for LAPACK from the source code.

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that’s the whole page, bestie 💖 — LAPACK Version 3.12.0, BLAS/SRC/dsymv.f(3), with the 22-October-1986 written-on date chilling in Further Details, and it was generated automatically by Doxygen for LAPACK from the source code. Mwah 🫶✨