A new method for solving symmetric circulant tridiagonal systems of linear equations

In this paper a new method for computing the solution of a linear system having a symmetric circulant tridiagonal matrix is presented. This special kind of system appears in many applications. After an appropriate partition of the system and the elimination of the last unknown, we apply the Woodbury formula to arrive at a very efficient and stable method, which is quite competitive with Gaussian elimination and with the modified double sweep method.