DLA_GERPVGRW(3)

💅 DLA_GERPVGRW(3) — Library Functions Manual ✨

okay so bestie, welcome to the Library Functions Manual. This page is the whole vibe for DLA_GERPVGRW, and we're keeping every single fact exactly where it belongs. 🫶

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🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dla_gerpvgrw.f

That's literally the NAME section: the source path. No cap. 🎀

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

double precision function DLA_GERPVGRW (n, ncols, a, lda, af, ldaf)
    DLA_GERPVGRW

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💖 Function/Subroutine Documentation 💖

Main-character signature, coming right up:

double precision function DLA_GERPVGRW (integer n, integer ncols, double
       precision, dimension( lda, * ) a, integer lda, double precision,
       dimension( ldaf, * ) af, integer ldaf)
DLA_GERPVGRW

🦋 Purpose 🦋

okay so DLA_GERPVGRW computes the reciprocal pivot growth factor norm(A)/norm(U). The norm is used. If this is much less than 1, the stability of the LU factorization of the (equilibrated) matrix A could be poor. This also means that the solution X, estimated condition numbers, and error bounds could be unreliable. 😭

lowkey important: if that reciprocal pivot growth factor is much less than 1, the stability can be poor and those estimates/bounds can be unreliable. Not me warning you, bestie — the page says it. 💅

🌈 Parameters 🌈

• N — N is INTEGER; it's the number of linear equations, i.e., the order of the matrix A. N >= 0.
• NCOLS — NCOLS is INTEGER; it's the number of columns of the matrix A. NCOLS >= 0.
• A — A is DOUBLE PRECISION array, dimension (LDA,N); on entry, it's the N-by-N matrix A.
• LDA — LDA is INTEGER; it's the leading dimension of the array A. LDA >= max(1,N).
• AF — AF is DOUBLE PRECISION array, dimension (LDAF,N); it holds the factors L and U from the factorization A = P*L*U as computed by DGETRF.
• LDAF — LDAF is INTEGER; it's the leading dimension of the array AF. LDAF >= max(1,N).

👑 Author 👑

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

Definition at line 98 of file dla_gerpvgrw.f.

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🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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and that's the page, bestie! 💖 Footer sign-off: LAPACK, Version 3.12.0, page source /home/abui..._gerpvgrw.f(3) — and no date was printed, so I'm not inventing one. periodt. ✨💅