STPMV(3)

🌸 NAME 🌸

Library Functions Manual energy, bestie — this page is titled stpmv.f(3), and it’s documenting this source file:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/BLAS/SRC/stpmv.f

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✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine STPMV (uplo, trans, diag, n, ap, x, incx)
    STPMV

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💅 Function/Subroutine Documentation 💅

subroutine STPMV (character uplo, character trans, character diag, integer n, real, dimension(*) ap, real, dimension(*) x, integer incx)

And the name on the tin is STPMV.

🎀 Purpose 🎀

Okay so here’s the whole vibe: STPMV performs one of the matrix-vector operations

x := A*x,   or   x := A**T*x,

where x is an n element vector and A is an n by n unit, or non-unit, upper or lower triangular matrix, supplied in packed form. Slay. 💅

🔥 Parameters 🔥

• UPLO — CHARACTER*1. On entry, UPLO says whether the matrix is upper or lower triangular:
  • UPLO = 'U' or 'u' → A is an upper triangular matrix.
  • UPLO = 'L' or 'l' → A is a lower triangular matrix.
• TRANS — CHARACTER*1. On entry, TRANS picks the operation:
  • TRANS = 'N' or 'n' → x := A*x.
  • TRANS = 'T' or 't' → x := A**T*x.
  • TRANS = 'C' or 'c' → x := A**T*x.
• DIAG — CHARACTER*1. On entry, DIAG tells us whether A is unit triangular:
  • DIAG = 'U' or 'u' → A is assumed to be unit triangular.
  • DIAG = 'N' or 'n' → A is not assumed to be unit triangular.
• N — INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero.
• AP — REAL array, dimension at least ( ( n*( n + 1 ) )/2 ). Here’s the packing tea:
  • Before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular 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 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.
  • Note that when DIAG = 'U' or 'u', the diagonal elements of A are not referenced, but are assumed to be unity.
• X — REAL array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element vector x. On exit, X is overwritten with the transformed vector x.
• INCX — INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.

🚨 Bestie, for real: INCX 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 141 of file stpmv.f.

🫶 Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

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💖 LAPACK Version 3.12.0 — source/page path: /home/abui...SRC/stpmv.f(3) — that’s the whole manual page, bestie. Periodt. 💅