Application user's needs for future architectures

Several trends are apparent in the use of high performance architectures by end-users in science and engineering. One prominent change is a shift towards more complicated geometric models which require irregular meshes and finite element type discretizations. A second related change is the need for more sophisticated data structures; many leading edge methods now rely on trees and networks where formerly they used simple arrays. A third change is an explosive growth in the sheer size of data involved, fueled by shifts to 3D modeling, availability of large databases, and dramatically reduced costs for online storage. A fourth major change is increasing reliance and use of high-level packages and libraries, where previously users developed their own code. The paper addresses these issues and proposes some of the support needed from future architectures and the software systems that provide access to them.