ZLAQSY(3)

💅 ZLAQSY(3) — Library Functions Manual 💅

okay so bestie, this is ZLAQSY(3) from the Library Functions Manual. The header path is the truncated /home/abui...RC/zlaqsy.f(3), and we are about to get into some very specific scaling-factor business. No cap. 💖

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🌸 NAME 🌸

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

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

Functions/Subroutines
    subroutine ZLAQSY (uplo, n, a, lda, s, scond, amax, equed)
        ZLAQSY scales a symmetric/Hermitian matrix, using scaling factors
        computed by spoequ.

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🦋 Function/Subroutine Documentation 🦋

subroutine ZLAQSY (character uplo, integer n, complex*16, dimension( lda, *
       ) a, integer lda, double precision, dimension( * ) s, double precision
       scond, double precision amax, character equed)

ZLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.

🌟 Purpose 🌟

ZLAQSY equilibrates a symmetric matrix A using the scaling factors in the vector S.

🍓 Parameters 🍓

• UPLO — CHARACTER*1. Specifies whether the upper or lower triangular part of the symmetric matrix A is stored.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — INTEGER. The order of the matrix A. N >= 0.
• A — COMPLEX*16 array, dimension (LDA,N). On entry, the symmetric matrix A. If UPLO = 'U', the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced.

On exit, if EQUED = 'Y', the equilibrated matrix: diag(S) * A * diag(S).

• LDA — INTEGER. The leading dimension of the array A. LDA >= max(N,1).
• S — DOUBLE PRECISION array, dimension (N). The scale factors for A.
• SCOND — DOUBLE PRECISION. Ratio of the smallest S(i) to the largest S(i).
• AMAX — DOUBLE PRECISION. Absolute value of largest matrix entry.
• EQUED — CHARACTER*1. Specifies whether or not equilibration was done.
  • = 'N': No equilibration.
  • = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).

🔥 Internal Parameters 🔥

• THRESH is a threshold value used to decide if scaling should be done based on the ratio of the scaling factors. If SCOND < THRESH, scaling is done.
• LARGE and SMALL are threshold values used to decide if scaling should be done based on the absolute size of the largest matrix element. If AMAX > LARGE or AMAX < SMALL, scaling is done.

👑 Author 👑

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

📌 Definition 📌

Definition at line 133 of file zlaqsy.f.

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👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole page, bestie 🫶 The source/version footnote is LAPACK Version 3.12.0, and the footer path is /home/abui...RC/zlaqsy.f(3). There's no date printed on this page, so I'm not making one up — bye! 💅