PZGBSV(l)

🌸 NAME 🌸

okay so bestie, welcome to PZGBSV(l), a LAPACK routine (version 1.5). This one is PZGBSV — and what it does is solve a system of linear equations A(1:N, JA:JA+N-1) * X = B(IB:IB+N-1, 1:NRHS). no cap, that's the whole mission. 💖

✨ SYNOPSIS ✨

the way that this signature is giving "call me exactly like this" energy:

SUBROUTINE PZGBSV( 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*16     A( * ), B( * ), WORK( * )

lowkey every single argument is right there, so don't skip a single one. 🫶

🎀 PURPOSE 🎀

PZGBSV solves a system of linear equations

where A(1:N, JA:JA+N-1) is an N-by-N complex banded distributed matrix with bandwidth BWL, BWU. it's giving "big matrix, but make it banded and distributed" vibes, fr fr. 🌈

Gaussian elimination with pivoting is used to factor a reordering of the matrix into P L U. yes bestie, pivoting is in the building, so pay attention. 💅

if you want the deep lore, go see PZGBTRF and PZGBTRS for details. they are the main characters of this story, iykyk. 👑

xoxo, that's the page 💋 — LAPACK version 1.5, 12 May 1997, signing off like the iconic source it is. 🦋