PCGBTRS(l)

📦 version 1.5, in ubuntu jammy

💖 NAME 💖

okay so bestie, PCGBTRS is here to solve a system of linear equations:

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

periodt. that's the whole gig. 💅

✨ SYNOPSIS ✨

SUBROUTINE PCGBTRS( TRANS, N, BWL, BWU, NRHS, A, JA, DESCA, IPIV, B, IB,
                    DESCB, AF, LAF, WORK, LWORK, INFO )

    CHARACTER       TRANS

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

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

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

like look at all those arguments, she's serving range fr fr 🎀

🌸 PURPOSE 🌸

okay so PCGBTRS solves a system of linear equations

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

or

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

where A(1:N, JA:JA+N-1) is the matrix used to produce the factors stored in A(1:N,JA:JA+N-1) and AF by PCGBTRF. 💖

A(1:N, JA:JA+N-1) is an N-by-N complex banded distributed matrix with bandwidth BWL, BWU.

🚨 no cap, routine PCGBTRF MUST be called first. like, it's not optional, bestie. if you skip it you're on your own and the vibes will be rancid. 😭

🌸 that's the whole page, iykyk 🌸

this was LAPACK routine version 1.5, dated 12 May 1997 🦋 — yeah she's an icon from another era and she still ate. go call PCGBTRF first tho, mwah 💜✨

📦 where this page comes from