PZGBTRS(l)

📦 version 1.5, in ubuntu jammy

💖 PZGBTRS 💖

ok so bestie, welcome to PZGBTRS(l) — that's the LAPACK routine, version 1.5, and she's here to solve linear equations for you. no cap. let's get into it 🫶

✨ NAME ✨

PZGBTRS — the girl who solves a system of linear equations

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

like literally that's her whole job and she eats every time 💅

🌸 SYNOPSIS 🌸

SUBROUTINE PZGBTRS( 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*16      A( * ), AF( * ), B( * ), WORK( * )

👑 PURPOSE 👑

ok so PZGBTRS 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 PZGBTRF.

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

⚠️ bestie listen. Routine PZGBTRF MUST be called first. no skipping. she will not work without her prequel. periodt. 💀

that's the whole page, mwah 💋 — this was PZGBTRS(l) from LAPACK routine version 1.5, dated 12 May 1997. oldie but a goodie, and she still slays 🌈⭐💜

📦 where this page comes from