A Fast Algorithm for Inverse of Five-Diagonal Matrices

The algorithm and explicit formulae for the elements of the inverse of five-diagonal matrices are presented.The results are obtained by relationships between the elements of the inverse and the elements of special twisted decompositions of it.Operation count of the algorithm have an advantage over that of the standard LU decomposition based on the Gaussian elimination,and some results can also be extended to block five-diagonal matrices.Result obtained improves result in the known corresponding references.