SLAQSP(3)

slaqsp.f(3) — Library Functions Manual 🌸

okay bestie, this is the slaqsp.f(3) page from the Library Functions Manual, and the header path is /home/abui...RC/slaqsp.f(3). We’re keeping every single fact intact — no cap. 💅✨

✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/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

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 — UPLO is CHARACTER*1. Specifies whether the upper or lower triangular part of the symmetric matrix A is stored.
  • = 'U': Upper triangular
  • = 'L': Lower triangular
• N — N is INTEGER. The order of the matrix A. N >= 0.
• AP — AP is 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 — S is REAL array, dimension (N). The scale factors for A.
• SCOND — SCOND is REAL. Ratio of the smallest S(i) to the largest S(i).
• AMAX — AMAX is REAL. Absolute value of largest matrix entry.
• EQUED — EQUED is 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  • = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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.

---

Sign-off from the footer, bestie: this is LAPACK, Version 3.12.0, and the page path is /home/abui...RC/slaqsp.f(3) 🫶💖 There’s no date line in the footer to report, so that’s the whole footer tea — periodt. ✨