BLAS/SRC/sspmv.f(3)

💅 NAME 💅

BLAS/SRC/sspmv.f — bestie, this is the sspmv page from the Library Functions Manual, and it's giving “packed symmetric matrix realness” in the best way. 💖

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

   subroutine sspmv (uplo, n, alpha, ap, x, incx, beta, y, incy)
           SSPMV

🌈 Function/Subroutine Documentation 🌈

   subroutine sspmv (character uplo, integer n, real alpha, real, dimension(*)
       ap, real, dimension(*) x, integer incx, real beta, real, dimension(*) y,
       integer incy)
       SSPMV

🎯 Purpose: 🎯

Okay so SSPMV 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, supplied in packed form. Slay. ✨

🎀 Parameters 🎀

• UPLO — CHARACTER*1. On entry, UPLO specifies whether the upper or lower triangular part of the matrix A is supplied in the packed array AP as follows:
  • UPLO = 'U' or 'u' — the upper triangular part of A is supplied in AP.
  • UPLO = 'L' or 'l' — the lower triangular part of A is supplied in AP.
• N — INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero.
• ALPHA — REAL. On entry, ALPHA specifies the scalar alpha.
• AP — REAL array, dimension at least ( ( n*( n + 1 ) )/2 ). Before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular part of the symmetric matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. Before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular part of the symmetric matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on.
• X — REAL array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element vector x.
• INCX — INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.
• BETA — REAL. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input.
• Y — REAL 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.
• 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 146 of file sspmv.f.

🖨️ Author 🖨️

Generated automatically by Doxygen for LAPACK from the source code.

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That's the whole page, bestie 💅✨ Signed off by LAPACK Version 3.12.0, page BLAS/SRC/sspmv.f(3), auto-generated by Doxygen from the source code. The routine itself says it was written on 22-October-1986, so yes — vintage icon behavior, and it still ate. 👑💖