An analytical approach: Explicit inverses of periodic tridiagonal matrices

Abstract

We derive an explicit formula for the inverse of a general, periodic, tridiagonal matrix. Our approach is to derive its LU factorization using backward continued fractions (BCF) which are an essential tool in number theory. We then use these formulae to construct an algorithm for inverting a general, periodic, tridiagonal matrix which we implement in Maple.1 Finally, we present the results of testing the efficiency of our new algorithm against another published implementation and against the library procedures available within Maple to invert a general matrix and to compute its determinant.