[BANANA] LAPACK seminar on Nov. 5

[Ming Gu]

               Math 290, Section 25, CS 298, Section 6,
                          FALL 2008
         (Matrix Computations and Scientific Computing)

We meet WEDNESDAYS 11:10 - noon in Room 380 Soda Hall, Berkeley campus.
The coordinators are Profs. J. Demmel (demmel at cs.berkeley.edu), 
M. Gu (mgu at math.berkeley.edu), and B. N. Parlett (parlett at math.berkeley.edu). 
The program will be a mixture of research talks and tutorials.
The tutorials will provide a partial sequel to Math 221.

Date: Nov. 5 
Speaker: Prof. Lexing Ying, University of Texas at Austin
Title: Butterfly Algorithm and Its Applications
Abstract: Oscillatory integral transforms and equations arise in many direct and
inverse problems pertaining to wave propagation phenomena. Examples
abound in fields including seismic migration, acoustic and
electromagnetic wave scattering, and radar imaging. However, the rapid
evaluation of these transforms is an challenging task due to the
oscillatory nature of the kernel.

In this talk, we first review the butterfly algorithm, which was
recently developed as a general approach for the rapid evaluation of
these oscillatory integrals. However, sometimes the practical
efficiency of the butterfly algorithm is limited by its high
preprocessing time and high storage requirement. In the second part of
this talk, we discuss two applications: (1) sparse Fourier transform
and (2) partial Fourier transform, where in each case these
constraints can be removed by using tools such as tensor product
decomposition and non-standard Chebyshev interpolation.

Date: Nov. 12
Speaker: John Bell, LBNL