Current research efforts

I am currently involved in the following research projects:

Development of direct methods: (With Mark Tygert and Vladimir Rokhlin.) Existing FMM techniques rapidly evaluate the product of an operator and a vector. New algorithms are under development for directly inverting operators, for multiplying operators, and for computing spectral decompositions of operators. Details.

Development of improved FMMs: (With Mark Tygert and Vladimir Rokhlin.) There is continuing research on improving the performance of existing fast multipole methods. Recent work include (a) very fast methods for 1D problems, (b) improved kernel-independent FMMs, (c) FMMs for general anisotropic elasticity in 3D.

Software development: A principal reason FMM based methods have not reached wider adaptation levels than they have is a lack of systematic software libraries. Writing a stable and efficient implementation of an FMM is a major software development project, especially for 3D codes. Work is currently under way on standardizing call sequences for fast solvers, and putting together libraries of "black-box" fast algorithms.

Customization of fast algorithms to specific applications: FMMs have the potential for very significantly accelerating computational models of biochemical processes. Construction of of fast software for simulating ion channels (with Bob Eisenberg and Dirk Gillespie) and large macro-molecules in ionic solutions in under way. (Joint work with Leslie Greengard and Denis Gueyffier at NYU.)


The following project is work by Mark Tygert and Vladimir Rokhlin alone. I would urge anyone interested in FMMs to take a look:

Fast spherical harmonics transforms: A stable O(N) algorithm for computing the spherical harmonics transform is is presented here. This algorithm can be applied to rapidly expand a given function in any orthogonal basis that is governed by a linear recurrence relation.