BLAS/SRC/dgemv.f(3)

Welcome to BLAS/SRC/dgemv.f(3), straight out of the Library Functions Manual — this is the DGEMV page, and yes, it's iconic. 💅

💖 NAME 💖

BLAS/SRC/dgemv.f — that's the name, bestie. This is the DGEMV BLAS routine page.

🌸 SYNOPSIS 🌸

Functions/Subroutines

• subroutine dgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy) — DGEMV

🦋 Function/Subroutine Documentation 🦋

subroutine dgemv (character trans, integer m, 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)

DGEMV

✨ Purpose ✨

DGEMV performs one of the matrix-vector operations, no cap:

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

where alpha and beta are scalars, x and y are vectors, and A is an m by n matrix.

🎀 Parameters 🎀

• TRANS — CHARACTER*1. On entry, TRANS picks the operation to be performed, bestie:
  • 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**T*x + beta*y.
• M — INTEGER. On entry, M specifies the number of rows of the matrix A. M must be at least zero.
• N — INTEGER. On entry, N specifies the number of columns of the matrix A. N must be at least zero.
• ALPHA — DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha.
• A — DOUBLE PRECISION array, dimension ( LDA, N ). Before entry, the leading m by n part of the array A must contain the matrix of coefficients.
• LDA — 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 — DOUBLE PRECISION 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 — INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.
• BETA — DOUBLE PRECISION. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input.
• Y — DOUBLE PRECISION 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.
• INCY — 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 157 of file dgemv.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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Okay that's the whole page, bestie. Footer vibes: LAPACK, Version 3.12.0, page BLAS/SRC/dgemv.f(3) — the footer as shown has no separate date line, just so you know. 🎀✨💖