SRC/cla_hercond_x.f(3)

✨ SRC/cla_hercond_x.f ✨

okay so this is a page out of the Library Functions Manual and it's all about one lil Fortran function that lives in SRC/cla_hercond_x.f 💅 buckle up bestie

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🌸 NAME 🌸

SRC/cla_hercond_x.f — that's the file, that's the name, no notes 🎀

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🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

• real function cla_hercond_x (uplo, n, a, lda, af, ldaf, ipiv, x, info, work, rwork) — CLA_HERCOND_X computes the infinity norm condition number of op(A)*diag(x) for Hermitian indefinite matrices. yes that's a whole mouthful and yes it ate 🔥

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👑 Function/Subroutine Documentation 👑

real function cla_hercond_x (character uplo, integer n, complex, dimension(
    lda, * ) a, integer lda, complex, dimension( ldaf, * ) af, integer ldaf,
    integer, dimension( * ) ipiv, complex, dimension( * ) x, integer info,
    complex, dimension( * ) work, real, dimension( * ) rwork)

CLA_HERCOND_X computes the infinity norm condition number of op(A)*diag(x) for Hermitian indefinite matrices. literally its whole personality 💖

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🎀 Purpose 🎀

!> !> CLA_HERCOND_X computes the infinity norm condition number of !> op(A) * diag(X) where X is a COMPLEX vector. !>

so yeah — infinity norm condition number of op(A) * diag(X), and X is a COMPLEX vector. that's the vibe check and it passed ✨

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🌈 Parameters 🌈

• UPLO

!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>

so 'U' means the upper triangle of A is what's stored, and 'L' means the lower triangle, periodt 🫶

• N

!> N is INTEGER !> The number of linear equations, i.e., the order of the !> matrix A. N >= 0. !>

it's the number of linear equations, aka the order of the matrix A, and it's gotta be N >= 0 — no negative nonsense allowed bestie 😤

• A

!> A is COMPLEX array, dimension (LDA,N) !> On entry, the N-by-N matrix A. !>

COMPLEX array, dimension (LDA,N). on entry it's the N-by-N matrix A. iconic 💅

• LDA

!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>

leading dimension of the array A, and it must satisfy LDA >= max(1,N) fr fr

• AF

!> AF is COMPLEX array, dimension (LDAF,N) !> The block diagonal matrix D and the multipliers used to !> obtain the factor U or L as computed by CHETRF. !>

COMPLEX array, dimension (LDAF,N). this one's holding the block diagonal matrix D plus the multipliers used to obtain the factor U or L, all as computed by CHETRF ⭐

• LDAF

!> LDAF is INTEGER !> The leading dimension of the array AF. LDAF >= max(1,N). !>

leading dimension of the array AF, and it's gotta be LDAF >= max(1,N) 🧚

• IPIV

!> IPIV is INTEGER array, dimension (N) !> Details of the interchanges and the block structure of D !> as determined by CHETRF. !>

INTEGER array, dimension (N) — the details of the interchanges and the block structure of D, as determined by CHETRF 🍓

• X

!> X is COMPLEX array, dimension (N) !> The vector X in the formula op(A) * diag(X). !>

COMPLEX array, dimension (N). it's the vector X in the formula op(A) * diag(X), which is literally the whole point of this function, slay 🌸

• INFO

!> INFO is INTEGER !> = 0: Successful exit. !> i > 0: The ith argument is invalid. !>

INTEGER status bestie: = 0 means successful exit 💚, and i > 0 means the *i*th argument is invalid 💀

• WORK

!> WORK is COMPLEX array, dimension (2*N). !> Workspace. !>

COMPLEX array, dimension (2*N). it's workspace, that's the whole job 🫶

• RWORK

!> RWORK is REAL array, dimension (N). !> Workspace. !>

REAL array, dimension (N). also workspace. also just doing its thing 🌈

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💜 Author 💜

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

look at that stacked author list, main character energy only 👑

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Definition at line 129 of file cla_hercond_x.f. — noted, cited, immortalized ⭐

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🙈 Author (again, but the automatic kind) 🙈

Generated automatically by Doxygen for LAPACK from the source code. not a human, just a robot doing its lil thing 🤖💅

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and that's the whole page!! no cap, every single flag and param intact 🎀

sign-off time bestie: this beauty comes from LAPACK, Version 3.12.0, and it's filed under SRC/cla_hercond_x.f(3). go forth and compute condition numbers responsibly 💖✨🦋