1. Department of Applied Mathematics; Lobachevsky University; Nizhny Novgorod Russia 603950
2. Department of Mathematical Software and Supercomputing Technologies; Lobachevsky University; Nizhny Novgorod Russia 603950
3. Institute of Supercomputing Technologies; Lobachevsky University; Nizhny Novgorod Russia 603950
4. Department of Theoretical Physics; University of Augsburg, Universitätßtrae 1; D-86135, Augsburg Germany