ZLACN2(3)

💖 ZLACN2 — Library Functions Manual 💖

okay so bestie, this is the glow-up of the ZLACN2 manual page, and the header path is /home/abui...RC/zlacn2.f(3). It’s giving “reverse communication but make it fashion,” and honestly? we love a matrix-norm estimator with main character energy. 💅✨

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zlacn2.f

yes, the NAME section is literally that whole path. iconic in a chaotic way 🎀

✨ SYNOPSIS ✨

Functions/Subroutines

• subroutine ZLACN2 (n, v, x, est, kase, isave) — ZLACN2 estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vector products.

🦋 Function/Subroutine Documentation 🦋

subroutine ZLACN2 (integer n, complex*16, dimension( * ) v, complex*16,
       dimension( * ) x, double precision est, integer kase, integer,
       dimension( 3 ) isave)

ZLACN2 estimates the 1-norm of a square matrix, using reverse communication for evaluating matrix-vector products.

🎀 Purpose: 🎀

!>
!> ZLACN2 estimates the 1-norm of a square, complex matrix A.
!> Reverse communication is used for evaluating matrix-vector products.
!>

💜 Parameters 💜

• N — N is INTEGER. The order of the matrix. N >= 1. no tiny-matrix nonsense here, bestie.
• V — V is COMPLEX*16 array, dimension (N). On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned, so don’t go looking for it 💀).
• X — X is COMPLEX*16 array, dimension (N). On an intermediate return, X should be overwritten by A * X, if KASE=1, A**H * X, if KASE=2, where A**H is the conjugate transpose of A, and ZLACN2 must be re-called with all the other parameters unchanged.
• EST — EST is DOUBLE PRECISION. On entry with KASE = 1 or 2 and ISAVE(1) = 3, EST should be unchanged from the previous call to ZLACN2. On exit, EST is an estimate (a lower bound) for norm(A). lower bound, but make it cute ✨
• KASE — KASE is INTEGER. On the initial call to ZLACN2, KASE should be 0. On an intermediate return, KASE will be 1 or 2, indicating whether X should be overwritten by A * X or A**H * X. On the final return from ZLACN2, KASE will again be 0.
• ISAVE — ISAVE is INTEGER array, dimension (3). ISAVE is used to save variables between calls to ZLACN2.

🌟 Author 🌟

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

🧚 Further Details: 🧚

!>
!>  Originally named CONEST, dated March 16, 1988.
!>
!>  Last modified:  April, 1999
!>
!>  This is a thread safe version of ZLACON, which uses the array ISAVE
!>  in place of a SAVE statement, as follows:
!>
!>     ZLACON     ZLACN2
!>      JUMP     ISAVE(1)
!>      J        ISAVE(2)
!>      ITER     ISAVE(3)
!>

🫶 Contributors: 🫶

Nick Higham, University of Manchester

📚 References: 📚

N.J. Higham, "FORTRAN codes for estimating the one-norm ofa real or complex matrix, with applications to condition estimation", ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988.

Definition at line 132 of file zlacn2.f.

📜 Author 📜

Generated automatically by Doxygen for LAPACK from the source code.

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bye bestie 🫶 this page is from LAPACK Version 3.12.0, and its footer path is /home/abui...RC/zlacn2.f(3). mwah 💋✨