SGTT01(3)

🌸 NAME 🌸

okay bestie, this is SGTT01(3) from the Library Functions Manual — and the header path-y bit is /home/abui...IN/sgtt01.f(3). The NAME section is literally this file, no cap:

• /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/sgtt01.f — that's the whole NAME vibe. 💅

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✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

Here's the subroutine, bestie — say it with me:

   subroutine SGTT01 (n, dl, d, du, dlf, df, duf, du2, ipiv, work, ldwork,
           rwork, resid)
           SGTT01

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📚 Function/Subroutine Documentation 📚

This one is giving SGTT01 main character energy. Full signature, exactly as it appears:

   subroutine SGTT01 (integer n, real, dimension( * ) dl, real, dimension( * )
       d, real, dimension( * ) du, real, dimension( * ) dlf, real, dimension( *
       ) df, real, dimension( * ) duf, real, dimension( * ) du2, integer,
       dimension( * ) ipiv, real, dimension( ldwork, * ) work, integer ldwork,
       real, dimension( * ) rwork, real resid)
       SGTT01

🎯 Purpose 🎯

SGTT01 reconstructs a tridiagonal matrix A from its LU factorization, then computes the residual:

norm(L*U - A) / ( norm(A) * EPS ),

where EPS is the machine epsilon. That's the whole purpose, periodt. 💖

🧾 Parameters 🧾

💖 N 💖

N is an INTEGER. It's the order of the matrix A, and bestie, N >= 0. 💅

🍓 DL 🍓

DL is a REAL array, dimension (N-1). It holds the (n-1) sub-diagonal elements of A.

🌸 D 🌸

D is a REAL array, dimension (N). It holds the diagonal elements of A.

🦋 DU 🦋

DU is a REAL array, dimension (N-1). It holds the (n-1) super-diagonal elements of A.

🎀 DLF 🎀

DLF is a REAL array, dimension (N-1). It holds the (n-1) multipliers that define the matrix L from the LU factorization of A.

✨ DF ✨

DF is a REAL array, dimension (N). It holds the n diagonal elements of the upper triangular matrix U from the LU factorization of A.

💜 DUF 💜

DUF is a REAL array, dimension (N-1). It holds the (n-1) elements of the first super-diagonal of U.

🌈 DU2 🌈

DU2 is a REAL array, dimension (N-2). It holds the (n-2) elements of the second super-diagonal of U.

👑 IPIV 👑

IPIV is an INTEGER array, dimension (N). These are the pivot indices; for 1 <= i <= n, row i of the matrix was interchanged with row IPIV(i). IPIV(i) will always be either i or i+1; IPIV(i) = i indicates a row interchange was not required. (iykyk pivot tea ☕)

🧚 WORK 🧚

WORK is a REAL array, dimension (LDWORK,N).

🔥 LDWORK 🔥

LDWORK is an INTEGER. It's the leading dimension of the array WORK, and LDWORK >= max(1,N). Important, bestie.

⭐ RWORK ⭐

RWORK is a REAL array, dimension (N).

💀 RESID 💀

RESID is a REAL. It's the scaled residual: norm(L*U - A) / (norm(A) * EPS). The math is mathing. 🫶

👑 Author 👑

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

📍 Definition at line 132 of file sgtt01.f 📍

Definition at line 132 of file sgtt01.f.

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✨ Author ✨

This page was generated automatically by Doxygen for LAPACK from the source code — very demure, very automated. 💖

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bye bestie 🫶 — footer vibes are LAPACK Version 3.12.0 and /home/abui...IN/sgtt01.f(3). Mwah 💋