Olavi Nevanlinna

Learn More
Restarted GMRES is known to be inefficient for solving shifted systems when the shifts are handled simultaneously. Variants have been proposed to enhance its performance. We show that another restarted method, restarted Full Orthogonaliza-tion Method (FOM), can effectively be employed. The total number of iterations of restarted FOM applied to all shifted(More)
This paper addresses and establishes some of the fundamental barriers in the theory of computations and finally settles the long standing computational spectral problem. Due to the barriers presented in this paper, there are many problems, some of them at the heart of computational theory, that do not fit into the classical frameworks of complexity theory.(More)
Iivo Vehviläinen: Applying mathematical finance tools to the competitive Nordic electricity market; Abstract: Deregulation of electricity industry has introduced competitive electricity markets that are similar to financial markets. Application of mathematical finance requires careful consideration of special characteristics of electricity markets. This(More)