James Baglama

Department of Mathematics
University of Rhode Island
Kingston, Rhode Island 02881
Office: Lippitt Hall 101A
Phone: 401-874-4412
Fax: 401-874-4454
E-Mail: jbaglama at math.uri.edu

Sakai login e-Campus URI Email	Rhode Island Chapter Pi Mu Epsilon	Curriculum Vitæ
Math 141	Education	Professional Links
Math 418	Papers	Quotes
Fall 2009 Schedule	Software	Calc-Bowl 2009

Education

Dec. 1997 Ph.D. in Applied Mathematics Kent State University
Advisors: Dr. Lothar Reichel and Dr. Arden Ruttan
Dec. 1991 M.S. in Applied Mathematics Youngstown State University
Advisor: Dr. John J. Buoni
Aug. 1990 B.S. in Mathematics Youngstown State University
Advisor: Dr. J. Douglas Faires

Professional Links

Software

EIGENVALUES
Symmetric
The program irbleigs.m is a MATLAB program for computing a few eigenvalues and associated eigenvectors located anywhere in spectrum of a large sparse Hermitian matrix. The irbleigs.m program is matrix-free, i.e., the matrix is accessed only through the evaluation of matrix-vector products. In particular the factorization of A is not demanded, nor is the solution of linear systems of equations with the matrix A. The code can also compute the generalized eigenpairs of certain generalized eigenvalue problems. A MATLAB GUI demo irbldemo.m is an easy to use interface with irbleigs.m that allows the user to quickly change the parameter options in irbleigs.m. This helps illustrates the different choices for the parameters available in irbleigs.m.

Click here to download the MATLAB code irbleigs.m.

Click here to download the MATLAB GUI demo irbldemo.m.

Non-Symmetric
The program ahbeigs.m is a MATLAB program for computing a few eigenvalues and associated eigenvectors located anywhere in spectrum of a large sparse non-symmetric matrix. The program ahbeigs.m is based on a block Arnoldi method that makes use of Householder reflections to maintain orthogonality and restarting is accomplished by augmentation of the Krylov subspace with Schur vectors. No factorization is required in order to find extreme eigenvalues, however factorization is performed when searching for non-extreme eigenvalues. The program can solve the standard or the generalized eigenvalue problem. Research supported by NSF grant DMS-0311786.

Click here to download the MATLAB code ahbeigs.m.

SINGULAR VALUES
The routine irblsvds.m is a MATLAB program for computing a few singular values and singular vectors of a m x n matrix A. irblsvds.m uses the (m+n) x (m+n) Hermitian matrix Z = [0 A; A' 0] and calls irbleigs.m to find a few eigenvalues and eigenvectors of the matrix Z. The singular values of A are the positive eigenvalues of Z, the "right" singular vectors V, correspond to the last n elements of the eigenvectors of Z, and the "left" singular vectors U, correspond to the first m elements of the eigenvectors of Z.

Click here to download the MATLAB code irblsvds.m.

The routines irlba.m and irlbablk.m are MATLAB programs for computing a few singular values and singular vectors of a m x n matrix A. irlba.m is a restarted Lanczos bidiagonalization method and irlbablk.m is a restarted block Lanczos bidiagonalization method. Restarting is carried out by augmentation of Krylov subspaces with either Ritz vectors or harmonic Ritz vectors.

Click here to download the MATLAB code irlba.m.

Click here to download the block MATLAB code irlbablk.m.

Click here to download the matrix hypatia.gz.

Papers

Iterative Methods for the Computation of a Few Eigenvalues of a Large Symmetric Matrix
(with D.Calvetti and L.Reichel), BIT, 36 (1996), pp. 400-421.
paper1.pdf
Computation of a few small eigenvalues of a large matrix with application to liquid crystal modeling
(with D. Calvetti, L. Reichel, and A. Ruttan) Journal of Computational Physics, 146, (1998) pp. 203-226.
paper2.pdf
Fast Leja points
(with D.Calvetti and L.Reichel) ETNA (1998) Vol. 7, (1998) pp. 126-140.
paper3.pdf
Adaptively Preconditioned GMRES Algorithms
(with D. Calvetti, G.H. Golub, and L. Reichel) ,SIAM J. Sci. Comput., 20, No. 1, (1998), pp. 243-269.
paper4.pdf
Qualitative behavior of a variable-yield simple food chain with an inhibiting nutrient
(with S. R. Jang), Mathematical Biosciences, 164, (2000) pp. 65-80.
paper5.pdf
Numerical Approximation of the Product of the Square Root of a Matrix With a Vector
(with E. J. Allen and S. K. Boyd) Linear Algebra and Its Applications, 310, (2000) pp. 167-181.
paper6.pdf
Dealing With Linear Dependence during the Iterations of the Restarted Block Lanczos Methods
Numerical Algorithms, 25, (2000) pp. 23-36.
paper7.pdf
A nutrient-prey-predator model with intratrophic predation
(with S. R. Jang), Applied Mathematics and Computation, 129, (2002), pp. 517-536.
IRBL: An Implicitly Restarted Block Lanczos Method for Large-Scale Hermitian Eigenproblems
(with D.Calvetti and L.Reichel) SIAM J. Sci. Comput., 24, No. 5, (2003), pp. 1650-1677.
paper9.pdf
irbleigs: A MATLAB program for computing a few eigenpairs of a large sparse Hermitian matrix
(with D.Calvetti and L.Reichel) TOMS, Vol. 29, No. 5, (2003), pp. 337-348.
paper10.pdf
Persistence in variable-yield nutrient-plankton models with nutrient recycling
(with S. R. Jang), Mathematical and Computer Modelling, 38 (2003), pp. 281-298.
paper11.pdf
Intratrophic predation in a simple food chain with fluctuating nutrient
(with S. R. Jang and P. Seshaiyer), Discrete and Continuous Dynamical Systems-Series B, Vol. 5, No. 2, May (2005), pp. 335-352.
paper12.pdf
Nutrient-plankton models with nutrient recycling
(with S. R. Jang) Computers and Mathematics with Application, Vol. 49, (2005), pp. 375-387.
paper13.pdf
Augmented Implicitly Restarted Lanczos Bidiagonalization Methods
(with L. Reichel) SIAM J. Sci. Comput., 27 (2005), pp. 19-42.
paper14.pdf
Droop models of nutrient-plankton interaction with intratrophic predation
(with S. R. Jang) Applied Mathematics and Computation, Vol. 169, (2005), pp. 1106-1128.
paper15.pdf
Nutrient-phytoplankton-zooplankton models with a toxin
(with S. R. Jang and J. Rick) Mathematical and Computer Modelling, Vol. 43, Issues 1-2, January (2006), pp. 105-118.
paper16.pdf
Decomposition methods for large linear discrete ill-posed problems
(with L. Reichel) Journal of Computation and Applied Mathematics, 18 (2007), pp. 332-343.
paper17.pdf
Augmented GMRES-type methods
(with L. Reichel) Numer. Linear Algebra Appl., 14 (2007), pp. 337-350.
paper18.pdf
Restarted Block Lanczos Bidiagonalization Methods
(with L. Reichel) Numerical Algorithms, 43 (2006), pp. 251-272.
paper19.pdf
Augmented Block Householder Arnoldi Method
Linear Algebra Appl.,Vol. 429, Issue 10, (2008) pp. 2315-2334
paper20.pdf
Plankton-toxin interaction with a variable input nutrient
(with S. R. Jang and J. Rick) Journal of Biological Dynamics, Volume 2, Issue 1 (2008), pp. 14 - 30

Quotes

"Experience is what you get when you didn't get what you wanted"

- Randy Pausch

"Don't waste time calculating your chances of success and failure. Just fix your aim and begin"

- Guan Yin Tzu

"An invisible red thread connects those who are destined to meet, regardless of time, place, or circumstance. The thread may stretch or tangle, but will never break."

- An ancient Chinese belief

"The most exciting phrase to hear in science, the one that heralds new discoveries, is not `Eureka!' but `That's funny...' "

- Isaac Asmiov

"Time and space are modes by which we think and not conditions in which we live."

- Albert Einstein

"It is a miracle that curiosity survives formal education."

- Albert Einstein

" It is the supreme art of the teacher to awaken joy in creative expression and knowledge."

- Albert Einstein

"I am not a teacher, I am an awakener."

- Robert Frost

"If nothing's fair, why can't it ever be unfair in *my* favor?"

- Calvin and Hobbes, "Calvin and Hobbes"

NOTICE: The information presented on this page represents the personal views, ideas, and opinions of the author. This is not an official University of Rhode Island web page. Links contained at this web site to other organizations, are presented as a service and neither constitute nor imply university endorsement or warranty.

James Baglama