TESTING/LIN/stpt01.f(3)

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version 3.12.1 · 3 versions
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🌸 NAME 🌸

okay so bestie, this page is TESTING/LIN/stpt01.f — yes, that whole file/page name — and it lives in the Library Functions Manual. We are officially in LAPACK testing territory 💅

✨ SYNOPSIS ✨

Functions/Subroutines

  • subroutine stpt01 (uplo, diag, n, ap, ainvp, rcond, work, resid) — STPT01

💫 Function/Subroutine Documentation 💫

the stpt01 subroutine 🎀

subroutine stpt01 (character uplo, character diag, integer n, real,
     dimension( * ) ap, real, dimension( * ) ainvp, real rcond, real,
     dimension( * ) work, real resid)

STPT01

Purpose 🦋

STPT01 computes the residual for a triangular matrix A times its inverse when A is stored in packed format:

RESID = norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ),

where EPS is the machine epsilon. slay, that's the whole mathematical vibe ✨

Parameters 🍓

  • UPLO — UPLO is CHARACTER*1. Specifies whether the matrix A is upper or lower triangular. = 'U': Upper triangular. = 'L': Lower triangular.
  • DIAG — DIAG is CHARACTER*1. Specifies whether or not the matrix A is unit triangular. = 'N': Non-unit triangular. = 'U': Unit triangular.
  • N — N is INTEGER. The order of the matrix A. N >= 0.
  • AP — AP is REAL array, dimension (N*(N+1)/2). The original upper or lower triangular matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = 'U', AP((j-1)*j/2 + i) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.
  • AINVP — AINVP is REAL array, dimension (N*(N+1)/2). On entry, the (triangular) inverse of the matrix A, packed columnwise in a linear array as in AP. On exit, the contents of AINVP are destroyed — like, gone gone 💀
  • RCOND — RCOND is REAL. The reciprocal condition number of A, computed as 1/(norm(A) * norm(AINV)).
  • WORK — WORK is REAL array, dimension (N).
  • RESID — RESID is REAL. norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ).

Author 👑

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

Definition at line 107 of file stpt01.f.

🪄 Author 🪄

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okay bye bestie 🫶 — the footer says LAPACK Version 3.12.0 and TESTING/LIN/stpt01.f(3), so that's the source/version/page situation at the very end. mwah 💋✨

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