cpttrs(3) on Linux
The text 796c2182646e, as Debian 2.2 (Potato), Debian 2.1 (Slink), Debian 2.0 (Hamm) shipped it.
solve a system of linear equations A * X = B with a Hermitian positive definite tridiagonal matrix A using the factorization A = U**H*D*U or A = L*D*L**H computed by CPTTRF