TESTING/LIN/ssyt01_aa.f(3)

🎀 NAME 🎀

TESTING/LIN/ssyt01_aa.f(3) — okay bestie, this page is from the Library Functions Manual and it's all about TESTING/LIN/ssyt01_aa.f. 💅

✨ SYNOPSIS ✨

🌸 Functions/Subroutines 🌸

subroutine ssyt01_aa (uplo, n, a, lda, afac, ldafac, ipiv, c, ldc,
    rwork, resid)
    SSYT01_AA

💖 Function/Subroutine Documentation 💖

   subroutine ssyt01_aa (character uplo, integer n, real, dimension( lda, * )
       a, integer lda, real, dimension( ldafac, * ) afac, integer ldafac,
       integer, dimension( * ) ipiv, real, dimension( ldc, * ) c, integer ldc,
       real, dimension( * ) rwork, real resid)
       SSYT01_AA

The main character is SSYT01_AA, obviously. 👑

🦋 Purpose 🦋

So SSYT01_AA reconstructs a symmetric indefinite matrix A from its block L*D*L' or U*D*U' factorization and computes the residual

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

where C is the reconstructed matrix and EPS is the machine epsilon. That's the whole vibe: rebuild A, then check how close C got to it. ✨

🍓 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 (LDA,N). The original symmetric matrix A.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
• AFAC — AFAC is REAL array, dimension (LDAFAC,N). The factored form of the matrix A. 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 SSYTRF.
• LDAFAC — LDAFAC is INTEGER. The leading dimension of the array AFAC. LDAFAC >= max(1,N).
• IPIV — IPIV is INTEGER array, dimension (N). The pivot indices from SSYTRF.
• 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 122 of file ssyt01_aa.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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Okay bestie, that's the whole page. Footer check: LAPACK, Version 3.12.0, page TESTING/LIN/ssyt01_aa.f(3) — no date listed, just those details, periodt. Mwah 💋💖✨