CLAQHB(3)

🌸 CLAQHB(3) — Library Functions Manual 🌸

okay so bestie, this is CLAQHB(3), and it lives in the Library Functions Manual. It's giving very serious linear-algebra energy, but make it cute. 🎀

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💖 NAME 💖

The NAME situation is literally this file path, no cap:

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

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✨ SYNOPSIS ✨

🫶 Functions/Subroutines 🫶

subroutine CLAQHB (uplo, n, kd, ab, ldab, s, scond, amax, equed)

CLAQHB scales a Hermitian band matrix, using scaling factors computed by cpbequ. slay. 💅

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🧚 Function/Subroutine Documentation 🧚

subroutine CLAQHB (character uplo, integer n, integer kd, complex, dimension( ldab, * ) ab, integer ldab, real, dimension( * ) s, real scond, real amax, character equed)

CLAQHB scales a Hermitian band matrix, using scaling factors computed by cpbequ.

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💅 Purpose:

CLAQHB equilibrates an Hermitian band matrix A using the scaling factors in the vector S.

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🎀 Parameters 🎀

• UPLO — UPLO is CHARACTER*1. It 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.
• KD — KD is INTEGER. The number of super-diagonals of the matrix A if UPLO = 'U', or the number of sub-diagonals if UPLO = 'L'. KD >= 0.
• AB — AB is COMPLEX array, dimension (LDAB,N). On entry, it's the upper or lower triangle of the symmetric band matrix A, stored in the first KD+1 rows of the array. The j-th column of A is stored in the j-th column of the array AB as follows: if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd).

On exit, if INFO = 0, it's the triangular factor U or L from the Cholesky factorization A = U**H *U or A = L*L**H of the band matrix A, in the same storage format as A. iconic. 🦋

• LDAB — LDAB is INTEGER. The leading dimension of the array AB. LDAB >= KD+1.
• 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. It 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).

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🌈 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 140 of file claqhb.f.

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🦋 Author 🦋

Generated automatically by Doxygen for LAPACK from the source code.

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mwah 💖 that's the whole page, bestie. The footer energy is LAPACK Version 3.12.0 with path /home/abui...RC/claqhb.f(3) — and no date is printed there, so I'm not inventing one. periodt. 👑