TESTING/LIN/sspt01.f(3)

🎀 NAME 🎀

okay bestie, this is TESTING/LIN/sspt01.f — straight from the Library Functions Manual, page TESTING/LIN/sspt01.f(3). It’s giving “LAPACK testing routine,” and the main character is SSPT01 in all its packed-matrix-reconstruction glory. 💅

✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

subroutine sspt01 (uplo, n, a, afac, ipiv, c, ldc, rwork, resid)

SSPT01

🫶 Function/Subroutine Documentation 🫶

Here’s the full signature, no cap:

subroutine sspt01 (character uplo, integer n, real, dimension( * ) a, real,
     dimension( * ) afac, integer, dimension( * ) ipiv, real, dimension( ldc,
     * ) c, integer ldc, real, dimension( * ) rwork, real resid)

SSPT01

✨ Purpose ✨

SSPT01 reconstructs a symmetric indefinite packed matrix A from its block L*D*L' or U*D*U' factorization and computes the residual, bestie:

norm( C - A ) / ( N * norm(A) * EPS ),

where C is the reconstructed matrix and EPS is the machine epsilon. Literally that’s the whole purpose, and it ate. 💖

🎀 Parameters 🎀

🌸 UPLO

UPLO is CHARACTER*1. It specifies whether the upper or lower triangular part of the symmetric matrix A is stored:

• = 'U': Upper triangular
• = 'L': Lower triangular

🌸 N

N is INTEGER. The number of rows and columns of the matrix A. N >= 0.

🌸 A

A is REAL array, dimension (N*(N+1)/2). The original symmetric matrix A, stored as a packed triangular matrix.

🌸 AFAC

AFAC is REAL array, dimension (N*(N+1)/2). The factored form of the matrix A, stored as a packed triangular matrix. AFAC contains the block diagonal matrix D and the multipliers used to obtain the factor L or U from the block L*D*L' or U*D*U' factorization as computed by SSPTRF.

🌸 IPIV

IPIV is INTEGER array, dimension (N). The pivot indices from SSPTRF.

🌸 C

C is REAL array, dimension (LDC,N).

🌸 LDC

LDC is INTEGER. The leading dimension of the array C. LDC >= max(1,N).

🌸 RWORK

RWORK is REAL array, dimension (N).

🌸 RESID

RESID is REAL.

If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS )
If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS )

💜 Author 💜

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

Definition at line 109 of file sspt01.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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okay that’s the whole page, bestie 💖 — footer vibes are source/version <purple>LAPACK</purple>, <purple>Version 3.12.0</purple>, page <purple>TESTING/LIN/sspt01.f(3)</purple> — and the footer didn’t hand me a separate date, so no invented date era for us 🙈. Mwah! 🫶✨