/home/abui...ercond_x.f(3)

🦋 NAME 🦋

ok so bestie, this whole page is about one file, and its full government name is literally:

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

that's the LAPACK source file path, it's from the Library Functions Manual (section 3, the library functions girlies ✨), and inside it lives exactly one iconic little function. buckle up 💅

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✨ SYNOPSIS ✨

Functions/Subroutines

double precision function ZLA_HERCOND_X (uplo, n, a, lda, af, ldaf,
    ipiv, x, info, work, rwork)

and what does she do, you ask? she computes the infinity norm condition number of op(A)*diag(x) for Hermitian indefinite matrices. that's the whole vibe. 🔥

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💖 Function/Subroutine Documentation 💖

double precision function ZLA_HERCOND_X (character uplo, integer n,
    complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension(
    ldaf, * ) af, integer ldaf, integer, dimension( * ) ipiv, complex*16,
    dimension( * ) x, integer info, complex*16, dimension( * ) work, double
    precision, dimension( * ) rwork)

ok so ZLA_HERCOND_X computes the infinity norm condition number of op(A)*diag(x) for Hermitian indefinite matrices. she's a double precision returning queen, so she's handing you back one double precision number at the end. periodt. 👑

Purpose:

!> !> ZLA_HERCOND_X computes the infinity norm condition number of !> op(A) * diag(X) where X is a COMPLEX*16 vector. !>

like literally that's her entire job description and she ate. 🎀

Parameters

• UPLO — UPLO is CHARACTER*1. and it's giving "which triangle are we living in today":
  • = 'U': Upper triangle of A is stored;
  • = 'L': Lower triangle of A is stored.
• N — N is INTEGER. the number of linear equations, i.e., the order of the matrix A. constraint check: N >= 0. 📏
• A — A is COMPLEX*16 array, dimension (LDA,N). on entry, the N-by-N matrix A. she's the main character.
• LDA — LDA is INTEGER. the leading dimension of the array A. and here's the rule: LDA >= max(1,N). no cap.
• AF — AF is COMPLEX*16 array, dimension (LDAF,N). it's the block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZHETRF. so like, the pre-chewed version 🍓
• LDAF — LDAF is INTEGER. the leading dimension of the array AF, and it must satisfy LDAF >= max(1,N). same energy as LDA, different array 💅
• IPIV — IPIV is INTEGER array, dimension (N). details of the interchanges and the block structure of D as determined by CHETRF. yes bestie, CHETRF — that's the name in the original, I don't make the rules 🌸
• X — X is COMPLEX*16 array, dimension (N). the vector X in the formula op(A) * diag(X). she's the diag girlie.
• INFO — INFO is INTEGER, and she's the vibe check:
  • = 0: Successful exit.
  • i > 0: The ith argument is invalid.
• WORK — WORK is COMPLEX*16 array, dimension (2*N). Workspace. (just a scratchpad, she works hard so the function doesn't have to 😭)
• RWORK — RWORK is DOUBLE PRECISION array, dimension (N). Workspace. (the real-valued scratchpad bestie 🫶)

Author

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

the whole squad collabed on this one and honestly? iconic. 🌈

Definition at line 130 of file zla_hercond_x.f.

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🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code. so nobody typed this page, a robot did, and she still served 💀

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and that's the whole page babes! 🎀 sign-off time: this was LAPACK, Version 3.12.0, and the page you're reading is /home/abui...ercond_x.f(3) — go read it again if you forgot anything, i'll wait 💖✨🦋