SRC/zsycon.f(3)

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💖 SRC/zsycon.f 💖

Okay bestie, welcome to the Library Functions Manual page for SRC/zsycon.f(3) — it’s giving big linear-algebra energy, and it’s literally all about ZSYCON. 🦋✨

🌸 NAME 🌸

SRC/zsycon.f — the source page, no cap. 💅

✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

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

ZSYCON 👑

🦋 Function/Subroutine Documentation 🦋

💜 subroutine zsycon 💜

subroutine zsycon (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)

ZSYCON 🌟

🌈 Purpose 🌈

Okay so ZSYCON estimates the reciprocal of the condition number (in the 1-norm) of a complex symmetric matrix A using the factorization A = U*D*U**T or A = L*D*L**T computed by ZSYTRF. 💖

An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). ✨

🎀 Parameters 🎀

  • UPLO — UPLO is CHARACTER*1. It 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**T;
    • = 'L': Lower triangular, form is A = L*D*L**T.
  • N — N is INTEGER. The order of the matrix A. N >= 0.
  • A — A is 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 ZSYTRF.
  • LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N).
  • IPIV — IPIV is INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by ZSYTRF.
  • ANORM — ANORM is DOUBLE PRECISION. The 1-norm of the original matrix A.
  • RCOND — RCOND is 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 — WORK is COMPLEX*16 array, dimension (2*N).
  • INFO — INFO is 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 📌

Definition at line 123 of file zsycon.f.

🌟 Author 🌟

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Signed, sealed, and slaying by LAPACK Version 3.12.0 — page SRC/zsycon.f(3) 💅✨

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