BLAS/SRC/stpmv.f(3)

NAME 💖

BLAS/SRC/stpmv.f — bestie, this is the Fortran source file for the stpmv routine, living its best life in the LAPACK BLAS folder. It's giving "I do one triangular matrix-vector thing and I do it flawlessly." 👑

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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)

STPMV

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🌸 Purpose:

Okay so listen, 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. No cap. 🫶

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🎀 Parameters

• UPLO — UPLO is CHARACTER*1. On entry, UPLO specifies whether the matrix is an upper or lower triangular matrix as follows:
  • UPLO = 'U' or 'u' — A is an upper triangular matrix.
  • UPLO = 'L' or 'l' — A is a lower triangular matrix.
• TRANS — TRANS is CHARACTER*1. On entry, TRANS specifies the operation to be performed as follows:
  • TRANS = 'N' or 'n' — x := A*x.
  • TRANS = 'T' or 't' — x := A**T*x.
  • TRANS = 'C' or 'c' — x := A**T*x.
• DIAG — DIAG is CHARACTER*1. On entry, DIAG specifies whether or not A is unit triangular as follows:
  • DIAG = 'U' or 'u' — A is assumed to be unit triangular.
  • DIAG = 'N' or 'n' — A is not assumed to be unit triangular.
• N — N is INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero.
• AP — AP is REAL array, dimension at least ( ( n*( n + 1 ) )/2 ). 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 — X is 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. She's transformed, literally. 💫
• INCX — INCX is INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.

⚠️ bestie do NOT pass INCX = 0, that's a whole vibe check fail.

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👑 Author

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

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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.

the way these legends wrote this in 1986 and it's still eating 💅

Definition at line 141 of file stpmv.f.

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🌈 Author

Generated automatically by Doxygen for LAPACK from the source code. Not a human, just a very efficient little robot bestie. 🤖✨

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Version 3.12.0 · Tue Nov 28 2023 12:08:41 · BLAS/SRC/stpmv.f(3)

okay that's the whole page, mwah 💖 thanks for reading to the end, you ate that fr fr 🫶🎀