SRC/dlacon.f(3)

✨ SRC/dlacon.f(3) ✨

okay bestie, welcome to the Library Functions Manual page for SRC/dlacon.f(3) — this is the dlacon subroutine's whole moment, and it's literally about estimating the 1-norm of a square matrix using reverse communication. 🫶

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🌸 NAME 🌸

SRC/dlacon.f

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🦋 SYNOPSIS 🦋

   Functions/Subroutines
       subroutine dlacon (n, v, x, isgn, est, kase)
           DLACON estimates the 1-norm of a square matrix, using reverse
           communication for evaluating matrix-vector products.

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🧚 Function/Subroutine Documentation 🧚

subroutine dlacon (integer n, double precision, dimension( * ) v, double
    precision, dimension( * ) x, integer, dimension( * ) isgn, double
    precision est, integer kase)

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

💖 Purpose 💖

okay so the actual purpose is this: DLACON estimates the 1-norm of a square, real matrix A. Reverse communication is used for evaluating matrix-vector products. no cap, that's the whole assignment. 🌟

🎀 Parameters 🎀

• N — N is INTEGER. It's the order of the matrix, and N >= 1. 👑
• V — V is a DOUBLE PRECISION array, dimension (N). On the final return, V = A*W, where EST = norm(V)/norm(W) (W is not returned). yes bestie, W is the invisible friend here. 🫥
• X — X is a DOUBLE PRECISION array, dimension (N). On an intermediate return, X should be overwritten by:

A * X,   if KASE=1,
A**T * X,  if KASE=2,

and DLACON must be re-called with all the other parameters unchanged. do not touch the other parameters, fr fr. 🙈

• ISGN — ISGN is an INTEGER array, dimension (N). that's it, that's the vibe. ✨
• EST — EST is DOUBLE PRECISION. On entry with KASE = 1 or 2 and JUMP = 3, EST should be unchanged from the previous call to DLACON. On exit, EST is an estimate (a lower bound) for norm(A). it's giving "lower bound but make it iconic." 💜
• KASE — KASE is INTEGER. On the initial call to DLACON, 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**T * X. On the final return from DLACON, KASE will again be 0. full circle moment. 🔥

🫶 Author 🫶

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

🌈 Contributors 🌈

• Nick Higham, University of Manchester.
• Originally named SONEST, dated March 16, 1988. vintage behavior, honestly. 🎀

📚 References 📚

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

📍 Definition 📍

Definition at line 114 of file dlacon.f.

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👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code. slay, automation. 🤖✨

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bestie, that's the whole page: LAPACK, Version 3.12.0, SRC/dlacon.f(3) — footer vibes complete. bye and stay normy 💅💖