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RESEARCH
COURSES
PUBLICATIONS
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RESEARCH
My interests are in high performance computing, specifically in areas that involve a liaison
between non-numerical (graph theory, machine learning) and numerical (large scale sparse linear solvers)
algorithms. Core areas of my investigation include combinatorial scientific computing and solution of
large scale sparse linear systems. Current research projects include;
Multimethod Solvers
Design of multimethod solvers involves the development of robust and scalable algorithms for
sparse linear systems by leveraging the strength of existing linear solvers. We developed the composite multimethod
solver where the linear system is applied to a sequence of solvers and the adaptive multimethod solver where
linear solvers are dynamically selected to match evolving linear system
properties.
Related Publications
(With: Dinesh
Kaushik,
Lois Curfman McInnes,
Boyana Norris,
Padma Raghavan)
Machine Learning for Linear
Solvers
Linear solvers are designed to cater to different solution
requirements and their
performance of these depend on
the properties of the linear systems being solved. Matching linear solvers to problem
characteristics can produce near optimal performance. However, given the wide variety of linear solvers, the
algorithmic options explode combinatorially. We use machine learning techniques to select
"good" solvers according to linear system characteristics.
Related Publications
(With: Victor
Eijkhout
,Yoav Freund,
Erika Fuentes,
David Keyes)
Automatic Differentiation
Automatic differentiation is based on evaluating the exact
derivatives of functions by using the chain rule,
in order to avoid the inevitable numerical errors of Taylor's method. Function sequences in the chain rule are
represented as directed acyclic graphs, therefore, algorithms for automatic differentiation can be derived through
combinatorial techniques. We are investigating the optimization
Hessian derivatives calculation through
detecting symmetry in the computational graph.
Related Publications
(With: Paul
Hovland)
Applications of
Graph
Embedding
Graph embedding is used to arrange vertices and
edges in an
aesthetically pleasing pattern on a two dimensional space. Extending this
concept to placement in an n-dimensional space we use embedding algorithms
to optimize data layout in caches and in other data clustering
applications like text mining. We are also considering use of embedding
algorithms for computational biology applications like modeling of
chromatin fibers.
(With: Anirban Chaterjee,
Mahmut Kandemir,
Padma Raghavan)
LINKS TO COURSES
LINKS TO SELECTED
PUBLICATIONS
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Robust Algorithms and Software for Parallel PDE-Based Simulations,
S. Bhowmick, L.McInnes, B.Norris,
and P.Raghavan, Proceedings of HPC
2004, the
Twelfth Special Symposium on High Perfomance Computing at the 2004 Advanced Simulation Technologies Conference, Arlington, VA, April 18-22,
2004.
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Combinatorial Algorithms Enabling
Computational Science: Tales From the Front, S. Bhowmick, E.
Boman, K. Devine, A. Gebremedhin, B.Hendrickson, P.Hovland, T. Munson and A. Pothen, Journal of Physics: Conference Series, Vol 46, 2006
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