**LA_GTSV** computes the solution to a real or complex linear system of
equations , where is a square tridiagonal matrix and
and are rectangular matrices or vectors. The
decomposition is used to factor the matrix as ,
where is a product of permutation and unit lower bidiagonal
matrices and is upper triangular with nonzeros in only the main
diagonal and first two superdiagonals. The
factored form of is then used to solve the above system.

Note: The system may be solved by interchanging the order of the arguments and .

Susan Blackford 2001-08-19