BLAS/SRC/stpmv.f(3)

💖 NAME 💖

Bestie, this is the BLAS/SRC/stpmv.f(3) page — the NAME section is literally just BLAS/SRC/stpmv.f, so consider yourself formally introduced to STPMV’s home file. 🫶

✨ SYNOPSIS ✨

🧚 Functions/Subroutines

• subroutine stpmv (uplo, trans, diag, n, ap, x, incx) — STPMV, the main character of this page. 👑

🎀 Function/Subroutine Documentation 🎀

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

🎯 Purpose:

Okay so 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, that’s the whole purpose. 💅

🧮 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. ✨
• INCX — INCX is INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Periodt. 💀

🌟 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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