TESTING/LIN/dget01.f(3)

Hey bestie 💖 this is the TESTING/LIN/dget01.f page from the Library Functions Manual, and it’s all about the DGET01 subroutine. No cap, it’s a little testing/lin icon ✨.

---

💖 NAME 💖

TESTING/LIN/dget01.f — that’s the page name, periodt 🎀

✨ SYNOPSIS ✨

🌈 Functions/Subroutines 🌈

subroutine dget01 (m, n, a, lda, afac, ldafac, ipiv, rwork, resid)

Function name: DGET01.

🦋 Function/Subroutine Documentation 🦋

subroutine dget01 (integer m, integer n, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( ldafac, * ) afac, integer ldafac, integer, dimension( * ) ipiv, double precision, dimension( * ) rwork, double precision resid)

The routine is called DGET01, and yes bestie, it’s that girl 💅.

🎀 Purpose 🎀

DGET01 reconstructs a matrix A from its L*U factorization and computes the residual

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

where EPS is the machine epsilon. Math? Reconstructed matrix? Residual? It’s giving very precise main-character energy ✨.

🍓 Parameters 🍓

• M — INTEGER. The number of rows of the matrix A. M >= 0.
• N — INTEGER. The number of columns of the matrix A. N >= 0.
• A — DOUBLE PRECISION array, dimension (LDA,N). The original M x N matrix A.
• LDA — INTEGER. The leading dimension of the array A. LDA >= max(1,M).
• AFAC — DOUBLE PRECISION array, dimension (LDAFAC,N). The factored form of the matrix A. AFAC contains the factors L and U from the L*U factorization as computed by DGETRF. It gets overwritten with the reconstructed matrix, and then with the difference L*U - A.
• LDAFAC — INTEGER. The leading dimension of the array AFAC. LDAFAC >= max(1,M).
• IPIV — INTEGER array, dimension (N). The pivot indices from DGETRF.
• RWORK — DOUBLE PRECISION array, dimension (M).
• RESID — DOUBLE PRECISION. norm(L*U - A) / ( N * norm(A) * EPS ).

Heads up bestie: AFAC is not staying cute and untouched — it gets overwritten with the reconstructed matrix, then with the difference L*U - A. That’s just the assignment, okay? 🫶

👑 Author 👑

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

Definition at line 105 of file dget01.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

---

Okay that’s the whole page, bestie 💖. Footer sign-off: LAPACK Version 3.12.0, source/page TESTING/LIN/dget01.f(3), and no date is shown in this footer, so I’m not inventing one — periodt 💅🎀.