carta
pspttrsv(3)

pspttrsv3

Solve a tridiagonal triangular system of linear equations a(1:n, ja:ja+n-1) * x = b(ib:ib+n-1, 1:nrhs)

Purpose

PSPTTRSV solves a tridiagonal triangular system of linear equations
or

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

where A(1:N, JA:JA+N-1) is a tridiagonal
triangular matrix factor produced by the
Cholesky factorization code PSPTTRF
and is stored in A(1:N,JA:JA+N-1) and AF.
The matrix stored in A(1:N, JA:JA+N-1) is either
upper or lower triangular according to UPLO,
and the choice of solving A(1:N, JA:JA+N-1) or A(1:N, JA:JA+N-1)^T is dictated by the user by the parameter TRANS.

Routine PSPTTRF MUST be called first.

From scalapack-doc 1.5-11 in Debian 11 (Bullseye). Parsed by carta from the page's man source.