PCGBSV(l)

📦 version 1.5, in ubuntu jammy

💖 PCGBSV — bestie edition 💖

the LAPACK routine that solves a system of linear equations A(1:N, JA:JA+N-1) * X = B(IB:IB+N-1, 1:NRHS)

like. it literally hands you the solution. no cap. 🫶

✨ SYNOPSIS ✨

SUBROUTINE PCGBSV( N, BWL, BWU, NRHS, A, JA, DESCA, IPIV, B, IB, DESCB,
                   WORK, LWORK, INFO )

    INTEGER        BWL, BWU, IB, INFO, JA, LWORK, N, NRHS

    INTEGER        DESCA( * ), DESCB( * ), IPIV( * )

    COMPLEX        A( * ), B( * ), WORK( * )

🎀 PURPOSE 🎀

okay so here's the tea 🍓 — PCGBSV solves a system of linear equations

A(1:N, JA:JA+N-1) * X = B(IB:IB+N-1, 1:NRHS)

where A(1:N, JA:JA+N-1) is an N-by-N complex banded distributed matrix with bandwidth BWL, BWU. she's banded, she's distributed, she's doing the most. 💅

Gaussian elimination with pivoting is what's used to factor a reordering of the matrix into P L U. iconic technique honestly.

if you want the full deets, go check out PCGBTRF and PCGBTRS. that's where the real lore lives. iykyk 👑

sign-off time 🌈 this was brought to you by LAPACK version 1.5, dated 12 May 1997, and the man page answers to the name PCGBSV(l). mwah 💋✨

📦 where this page comes from