SRC/zlaqhp.f(3)

🫶 SRC/zlaqhp.f(3) 🫶

From the Library Functions Manual. okay bestie, this is the page for SRC/zlaqhp.f, and it’s all about the zlaqhp subroutine doing its packed-Hermitian scaling thing 💅

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✨ NAME ✨

SRC/zlaqhp.f

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🌸 SYNOPSIS 🌸

🛠️ Functions/Subroutines

• subroutine zlaqhp (uplo, n, ap, s, scond, amax, equed) — ZLAQHP scales a Hermitian matrix stored in packed form.

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💖 Function/Subroutine Documentation 💖

subroutine zlaqhp (character uplo, integer n, complex*16, dimension( * ) ap,
    double precision, dimension( * ) s, double precision scond, double
    precision amax, character equed)

ZLAQHP scales a Hermitian matrix stored in packed form.

🦋 Purpose

ZLAQHP equilibrates a Hermitian matrix A using the scaling factors in the vector S.

🎀 Parameters

• UPLO — CHARACTER*1. Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — INTEGER. The order of the matrix A. N >= 0.
• AP — COMPLEX*16 array, dimension (N*(N+1)/2). On entry, the upper or lower triangle of the Hermitian 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 — 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  • = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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.

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👑 Author 👑

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

Definition at line 125 of file zlaqhp.f.

🧚 Author (auto-generated bit) 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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Byeee bestie 🫶 this one’s from LAPACK, Version 3.12.0, and the page is SRC/zlaqhp.f(3) ✨