SRC/slaqsp.f(3)

SRC/slaqsp.f 💅

okay so this page is from the Library Functions Manual, and it's all about SRC/slaqsp.f — packed-matrix scaling realness, bestie ✨

✨ NAME ✨

SRC/slaqsp.f

✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine slaqsp (uplo, n, ap, s, scond, amax, equed) — SLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ.

✨ Function/Subroutine Documentation ✨

subroutine slaqsp (character uplo, integer n, real, dimension( * ) ap, real, dimension( * ) s, real scond, real amax, character equed)

SLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ.

💖 Purpose 💖

SLAQSP 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.
• AP — REAL array, dimension (N*(N+1)/2). On entry, the upper or lower triangle of the symmetric matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. On exit, the equilibrated matrix: diag(S) * A * diag(S), in the same storage format as A.
• S — REAL array, dimension (N). The scale factors for A.
• SCOND — REAL. Ratio of the smallest S(i) to the largest S(i).
• AMAX — REAL. 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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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 at line 124 of file slaqsp.f.

✨ Author ✨

Generated automatically by Doxygen for LAPACK from the source code.

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okay bestie, that's the whole vibe 💅 this page is from LAPACK Version 3.12.0, and the file is SRC/slaqsp.f(3) — periodt 💖✨