scholarly journals Profiling General-Purpose Fast Multipole Method (FMM) Using Human Head Topology

2020 ◽  
pp. 347-381
Author(s):  
Dung Ngoc Pham
Keyword(s):  
Fast Multipole Method ◽  
Human Head ◽  
General Purpose ◽  
Test Cases ◽  
Fast Multipole ◽  
Helmholtz Equations ◽  
Modeling Methods ◽  
Wide Range ◽  
Multipole Method ◽  
Test Objects

AbstractIn this study, we characterize the performance of the fast multipole method (FMM) in solving the Laplace and Helmholtz equations. We use the FMM library developed by the group of Dr. L. Greengard. This version of the FMM algorithm is multilayer with no priori limit on the number of levels of the FMM tree, although, after about thirty levels, there may be floating point issues. A collection of high-resolution human head models is used as test objects. We perform a detailed analysis of the runtime and memory consumption of the FMM in a wide range of frequencies, problem sizes, and precisions required. Although we focus on two-manifold test cases, the results are generalizable to other topologies as well. The tests are conducted on both Windows and Linux platforms. The results obtained in this study can serve as a general benchmark for the performance of FMM. It can also be employed to pre-estimate the efficiency of numerical modeling methods (e.g., the boundary element method) accelerated by FMM.

scholarly journals A Software Toolkit for TMS Electric-Field Modeling with Boundary Element Fast Multipole Method: An Efficient MATLAB Implementation

2020 ◽  
Author(s):  
Sergey N. Makarov ◽  
William A. Wartman ◽  
Mohammad Daneshzand ◽  
Kyoko Fujimoto ◽  
Tommi Raij ◽  
...  
Keyword(s):  
High Resolution ◽  
Boundary Element ◽  
Electric Fields ◽  
Fast Multipole Method ◽  
Human Head ◽  
Head Model ◽  
Fast Multipole ◽  
Software Toolkit ◽  
Model Repository ◽  
Multipole Method

AbstractBackgroundTranscranial magnetic stimulation (TMS) is currently the only non-invasive neurostimulation modality that enables painless and safe supra-threshold stimulation by employing electromagnetic induction to efficiently penetrate the skull. Accurate, fast, and high resolution modeling of the electric fields (E-fields) may significantly improve individualized targeting and dosing of TMS and therefore enhance the efficiency of existing clinical protocols as well as help establish new application domains.ObjectiveTo present and disseminate our TMS modeling software toolkit, including several new algorithmic developments, and to apply this software to realistic TMS modeling scenarios given a high-resolution model of the human head including cortical geometry and an accurate coil model.MethodThe recently developed charge-based boundary element fast multipole method (BEM-FMM) is employed as an alternative to the 1st order finite element method (FEM) most commonly used today. The BEM-FMM approach provides high accuracy and unconstrained field resolution close to and across cortical interfaces. Here, the previously proposed BEM-FMM algorithm has been improved in several novel ways.Results and ConclusionsThe improvements resulted in a threefold increase in computational speed while maintaining the same solution accuracy. The computational code based on the MATLAB® platform is made available to all interested researchers, along with a coil model repository and examples to create custom coils, head model repository, and supporting documentation. The presented software toolkit may be useful for post-hoc analyses of navigated TMS data using high-resolution subject-specific head models as well as accurate and fast modeling for the purposes of TMS coil/hardware development.

scholarly journals Taylor expansion based fast multipole method for 3-D Helmholtz equations in layered media

2020 ◽  
Vol 401 ◽  
pp. 109008 ◽  
Author(s):  
Bo Wang ◽  
Duan Chen ◽  
Bo Zhang ◽  
Wenzhong Zhang ◽  
Min Hyung Cho ◽  
...  
Keyword(s):  
Taylor Expansion ◽  
Fast Multipole Method ◽  
Layered Media ◽  
Fast Multipole ◽  
Helmholtz Equations ◽  
Multipole Method

A Fourier-series-based kernel-independent fast multipole method

2011 ◽  
Vol 230 (15) ◽  
pp. 5807-5821 ◽  
Author(s):  
Bo Zhang ◽  
Jingfang Huang ◽  
Nikos P. Pitsianis ◽  
Xiaobai Sun
Keyword(s):  
Fourier Series ◽  
Fast Multipole Method ◽  
Fast Multipole ◽  
Multipole Method

The Fast Multipole Method in Canonical Ensemble Dynamics on Massively Parallel Computers

1992 ◽  
Vol 278 ◽  
Author(s):  
Steven R. Lustig ◽  
J.J. Cristy ◽  
D.A. Pensak
Keyword(s):  
Canonical Ensemble ◽  
Yukawa Potential ◽  
Direct Method ◽  
Fast Multipole Method ◽  
Parallel Computers ◽  
Massively Parallel ◽  
Fast Multipole ◽  
Massively Parallel Computers ◽  
Multipole Method ◽  
Execution Times

AbstractThe fast multipole method (FMM) is implemented in canonical ensemble particle simulations to compute non-bonded interactions efficiently with explicit error control. Multipole and local expansions have been derived to implement the FMM efficiently in Cartesian coordinates for soft-sphere (inverse power law), Lennard- Jones, Morse and Yukawa potential functions. Significant reductions in execution times have been achieved with respect to the direct method. For a given number, N, of particles the execution times of the direct method scale asO(N2). The FMM execution times scale asO(N) on sequential workstations and vector processors and asymptotically0(logN) on massively parallel computers. Connection Machine CM-2 and WAVETRACER-DTC parallel FMM implementations execute faster than the Cray-YMP vectorized FMM for ensemble sizes larger than 28k and 35k, respectively. For 256k particle ensembles the CM-2 parallel FMM is 12 times faster than the Cray-YMP vectorized direct method and 2.2 times faster than the vectorized FMM. For 256k particle ensembles the WAVETRACER-DTC parallel FMM is 33 times faster than the Cray-YMP vectorized direct method.

A new version of the Fast Multipole Method for the Laplace equation in three dimensions

Acta Numerica ◽  
1997 ◽  
Vol 6 ◽  
pp. 229-269 ◽  
Author(s):  
Leslie Greengard ◽  
Vladimir Rokhlin
Keyword(s):  
Laplace Equation ◽  
Fast Multipole Method ◽  
High Accuracy ◽  
Three Dimensions ◽  
Potential Fields ◽  
Diagonal Form ◽  
Fast Multipole ◽  
Reasonable Cost ◽  
Multipole Method ◽  
Translation Operators

We introduce a new version of the Fast Multipole Method for the evaluation of potential fields in three dimensions. It is based on a new diagonal form for translation operators and yields high accuracy at a reasonable cost.

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