DGET02(3)

💅 NAME 💅

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/dget02.f — like, that's literally the whole name bestie, it's a Fortran file living its best life in the LAPACK testing directory 🎀

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✨ SYNOPSIS ✨

Functions/Subroutines 🌸

subroutine DGET02 (trans, m, n, nrhs, a, lda, x, ldx, b, ldb, rwork,
    resid)

DGET02 — that's her, that's the icon 💅

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🦋 Function/Subroutine Documentation 🦋

subroutine DGET02 (character trans, integer m, integer n, integer nrhs,
    double precision, dimension( lda, * ) a, integer lda, double precision,
    dimension( ldx, * ) x, integer ldx, double precision, dimension( ldb, *
    ) b, integer ldb, double precision, dimension( * ) rwork, double
    precision resid)

DGET02 👑

🎯 Purpose 🎯

Okay so listen, bestie — DGET02 computes the residual for a solution of a system of linear equations op(A)*X = B:

RESID = norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS ),

where op(A) = A or A**T, depending on TRANS, and EPS is the machine epsilon. The norm used is the 1-norm. No cap, that's the whole vibe check: how far off is your answer, scaled so the number actually means something 💖

🧚 Parameters 🧚

• TRANS — TRANS is CHARACTER*1 and it specifies the form of the system of equations, iykyk:
  • = 'N': A * X = B (No transpose)
  • = 'T': A**T * X = B (Transpose)
  • = 'C': A**H * X = B (Conjugate transpose = Transpose)
• M — M is INTEGER, the number of rows of the matrix A. M >= 0. ✨
• N — N is INTEGER, the number of columns of the matrix A. N >= 0. ✨
• NRHS — NRHS is INTEGER, the number of columns of B, the matrix of right hand sides. NRHS >= 0. 🫶
• A — A is DOUBLE PRECISION array, dimension (LDA,N). The original M x N matrix A. 🎀
• LDA — LDA is INTEGER, the leading dimension of the array A. LDA >= max(1,M). Don't mess this one up fr fr.
• X — X is DOUBLE PRECISION array, dimension (LDX,NRHS). The computed solution vectors for the system of linear equations. Main character energy, honestly 💅
• LDX — LDX is INTEGER, the leading dimension of the array X. If TRANS = 'N', LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,M). ⭐
• B — B is DOUBLE PRECISION array, dimension (LDB,NRHS). On entry, the right hand side vectors for the system of linear equations. On exit, B is overwritten with the difference B - op(A)*X. 👀 Yeah, she gets clobbered — that's not a bug, that's just how she does it.
• LDB — LDB is INTEGER, the leading dimension of the array B. If TRANS = 'N', LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N). 🌈
• RWORK — RWORK is DOUBLE PRECISION array, dimension (M). 🍓
• RESID — RESID is DOUBLE PRECISION, the maximum over the number of right hand sides of

norm(B - op(A)*X) / ( norm(op(A)) * norm(X) * EPS )

That's your final girl, the number you actually came here for 🔥

Heads up bestie: the size constraints in this parameter list (M >= 0, N >= 0, LDX >= max(1,N), and all the rest) are non-negotiable — respect the leading dimensions or it's giving undefined behaviour 💀

👑 Author 👑

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

Definition at line 133 of file dget02.f. 📍

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💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code. Not me writing this by hand, the robots did it 🤖✨

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That's the whole page, bestie! LAPACK Version 3.12.0, and this little beauty came from /home/abui...IN/dget02.f(3) — slay, go check your residuals, ily 🫶💖