SRC/zhecon.f(3)

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version 3.12.1 · 7 versions
, in arch rolling

🎀 NAME 🎀

okay so bestie, quick vibe check: this page is SRC/zhecon.f, and it’s from the Library Functions Manual. Yes, we’re in Unix manual territory, but make it group chat. 💅✨

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

subroutine zhecon (uplo, n, a, lda, ipiv, anorm, rcond, work, info)

🦋 Function/Subroutine Documentation 🦋

Here’s the full signature, no cap:

subroutine zhecon (character uplo, integer n, complex*16, dimension( lda, *
    ) a, integer lda, integer, dimension( * ) ipiv, double precision anorm,
    double precision rcond, complex*16, dimension( * ) work, integer info)

💅 ZHECON 💅

💖 Purpose 💖

ZHECON estimates the reciprocal of the condition number of a complex Hermitian matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by ZHETRF.

An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as:

RCOND = 1 / (ANORM * norm(inv(A)))

Periodt. That’s the whole routine’s main-character moment. 🔥

🍓 Parameters 🍓

  • UPLO — CHARACTER*1. Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.
    • = 'U': Upper triangular, form is A = U*D*U**H;
    • = 'L': Lower triangular, form is A = L*D*L**H.
  • N — INTEGER. The order of the matrix A. N >= 0.
  • A — COMPLEX*16 array, dimension (LDA,N). The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by ZHETRF.
  • LDA — INTEGER. The leading dimension of the array A. LDA >= max(1,N).
  • IPIV — INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by ZHETRF.
  • ANORM — DOUBLE PRECISION. The 1-norm of the original matrix A.
  • RCOND — DOUBLE PRECISION. The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine.
  • WORK — COMPLEX*16 array, dimension (2*N).
  • INFO — INTEGER.
    • = 0: successful exit
    • < 0: if INFO = -i, the i-th argument had an illegal value

👑 Author 👑

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

📌 Definition at line 123 of file zhecon.f.

💫 Author 💫

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That’s the whole page, bestie 💜. Big bye-bye kiss to LAPACK Version 3.12.0 and the SRC/zhecon.f(3) source — mwah! 🫶✨

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