ZGTT01(3)

💖 NAME 💖

Bestie, this is the zgtt01.f(3) page from the Library Functions Manual — and the star of the show is literally this file path:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/zgtt01.f

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ZGTT01 (n, dl, d, du, dlf, df, duf, du2, ipiv, work, ldwork,
    rwork, resid)
    ZGTT01

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🛠️ Function/Subroutine Documentation 🛠️

Here's the full signature, exactly as it appears, bestie:

subroutine ZGTT01 (integer n, complex*16, dimension( * ) dl, complex*16,
    dimension( * ) d, complex*16, dimension( * ) du, complex*16, dimension(
    * ) dlf, complex*16, dimension( * ) df, complex*16, dimension( * ) duf,
    complex*16, dimension( * ) du2, integer, dimension( * ) ipiv,
    complex*16, dimension( ldwork, * ) work, integer ldwork, double
    precision, dimension( * ) rwork, double precision resid)
    ZGTT01

🎯 Purpose

Okay so ZGTT01 reconstructs a tridiagonal matrix A from its LU factorization and computes the residual:

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

where EPS is the machine epsilon. That's the whole assignment, and it ate. Periodt. 💅

🌸 Parameters

• N — N is INTEGER. The order of the matrix A. N >= 0.
• DL — DL is COMPLEX*16 array, dimension (N-1). The (n-1) sub-diagonal elements of A.
• D — D is COMPLEX*16 array, dimension (N). The diagonal elements of A.
• DU — DU is COMPLEX*16 array, dimension (N-1). The (n-1) super-diagonal elements of A.
• DLF — DLF is COMPLEX*16 array, dimension (N-1). The (n-1) multipliers that define the matrix L from the LU factorization of A.
• DF — DF is COMPLEX*16 array, dimension (N). The n diagonal elements of the upper triangular matrix U from the LU factorization of A.
• DUF — DUF is COMPLEX*16 array, dimension (N-1). The (n-1) elements of the first super-diagonal of U.
• DU2 — DU2 is COMPLEX*16 array, dimension (N-2). The (n-2) elements of the second super-diagonal of U.
• IPIV — IPIV is INTEGER array, dimension (N). 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.
• WORK — WORK is COMPLEX*16 array, dimension (LDWORK,N).
• LDWORK — LDWORK is INTEGER. The leading dimension of the array WORK. LDWORK >= max(1,N).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N).
• RESID — RESID is DOUBLE PRECISION. The scaled residual: norm(L*U - A) / (norm(A) * EPS).

👑 Author

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

Definition at line 132 of file zgtt01.f.

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💫 Author 💫

This page was generated automatically by Doxygen for LAPACK from the source code. Not me doing manual labor — the robots handled it. 🤖✨

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And that's the whole vibe check, bestie: signed with LAPACK Version 3.12.0, and the footer path is /home/abui...IN/zgtt01.f(3). No date in the footer, just that source/version energy. 🫶💖