SRC/zgecon.f(3)

🎀 NAME 🎀

okay so this page is SRC/zgecon.f — header vibes: SRC/zgecon.f(3) — and it's serving Library Functions Manual energy, bestie ✨. It's all about ZGECON, and honestly? iconic. 💅

✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

• subroutine zgecon (norm, n, a, lda, anorm, rcond, work, rwork, info) — ZGECON 💖

💜 Function/Subroutine Documentation 💜

🌸 subroutine zgecon 🌸

subroutine zgecon (character norm, integer n, complex*16, dimension( lda, * ) a, integer lda, double precision anorm, double precision rcond, complex*16, dimension( * ) work, double precision, dimension( * ) rwork, integer info)

ZGECON — say it with me, bestie 👑.

🎀 Purpose 🎀

okay so ZGECON estimates the reciprocal of the condition number of a general complex matrix A, in either the 1-norm or the infinity-norm, using the LU factorization computed by ZGETRF. No cap ✨.

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

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

literally that formula, bestie 🫶.

🧚 Parameters 🧚

• NORM — NORM is CHARACTER*1. It specifies whether the 1-norm condition number or the infinity-norm condition number is required:
  • = '1' or 'O': 1-norm;
  • = 'I': Infinity-norm.
• N — N is INTEGER; the order of the matrix A. N >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). It holds the factors L and U from the factorization A = P*L*U as computed by ZGETRF.
• LDA — LDA is INTEGER; the leading dimension of the array A. LDA >= max(1,N).
• ANORM — ANORM is DOUBLE PRECISION. If NORM = '1' or 'O', it's the 1-norm of the original matrix A. If NORM = 'I', it's the infinity-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/(norm(A) * norm(inv(A))).
• WORK — WORK is COMPLEX*16 array, dimension (2*N).
• RWORK — RWORK is DOUBLE PRECISION array, dimension (2*N).
• INFO — INFO is INTEGER:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value. NaNs are illegal values for ANORM, and they propagate to the output parameter RCOND. Infinity is illegal for ANORM, and it propagates to the output parameter RCOND as 0.
  • = 1: if RCOND = NaN, or RCOND = Inf, or the computed norm of the inverse of A is 0. In the latter, RCOND = 0 is returned.

🌈 Author 🌈

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

Definition at line 130 of file zgecon.f. 🫶

⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code. 🎀

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okay that's the whole page, bestie 👋 — it's from SRC/zgecon.f(3) in the Library Functions Manual, and the footer is serving LAPACK Version 3.12.0 realness. mwah 💋✨