PDPTSV(l)

okay so bestie, meet PDPTSV(l) — a LAPACK routine (version 1.5). she's iconic, she solves linear equations, and she's about to explain herself. 💅

✨ NAME ✨

PDPTSV — solves a system of linear equations like A(1:N, JA:JA+N-1) * X = B(IB:IB+N-1, 1:NRHS). periodt. 💖

✨ SYNOPSIS ✨

here's the whole subroutine signature, no cap, copy it exactly:

       SUBROUTINE PDPTSV( N, NRHS, D, E, JA, DESCA, B, IB, DESCB, WORK, LWORK,
                          INFO )

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

           INTEGER        DESCA( * ), DESCB( * )

           DOUBLE         PRECISION B( * ), D( * ), E( * ), WORK( * )

✨ PURPOSE ✨

okay so PDPTSV solves a system of linear equations where A(1:N, JA:JA+N-1) is an N-by-N real tridiagonal symmetric positive definite distributed matrix. she uses Cholesky factorization to factor a reordering of the matrix into L L'. no cap. if you want the deets, go see PDPTTRF and PDPTTRS. 🫶

💖 this has been PDPTSV(l) from LAPACK version 1.5, dated 12 May 1997. stay slay, bestie. 💅✨