SIAM Student Chapter Seminar: Difference between revisions
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__NOTOC__ | __NOTOC__ | ||
*'''When:''' | *'''When:''' Fridays at 1:30 PM unless noted otherwise | ||
*'''Where:''' | *'''Where:''' 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments) | ||
*'''Organizers:''' | *'''Organizers:''' Yahui Qu, Peiyi Chen and Zaidan Wu | ||
*'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] | *'''Faculty advisers:''' [http://www.math.wisc.edu/~jeanluc/ Jean-Luc Thiffeault], [http://pages.cs.wisc.edu/~swright/ Steve Wright] | ||
*'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu]. | *'''To join the SIAM Chapter mailing list:''' email [mailto:siam-chapter+join@g-groups.wisc.edu siam-chapter+join@g-groups.wisc.edu]. | ||
*'''Zoom link:''' https://uwmadison.zoom.us/j/97976615799?pwd=U2xFSERIcnR6M1Y1czRmTjQ1bTFJQT09 | |||
*'''Passcode: 281031''' | |||
== Spring 2025 == | |||
{| class="wikitable" | |||
|+ | |||
{| | |Date | ||
|Location | |||
|Speaker | |||
|Title | |||
| | |||
| | |||
| | |||
| | |||
| | |||
|- | |- | ||
| | |03/07 | ||
| | |9th floor | ||
| | |Ang Li | ||
|Applying for postdocs and different industry jobs ... at the | |||
same time | |||
|- | |- | ||
|04/04 | |||
|9th floor | |||
|Borong Zhang | |||
|Stochastic Multigrid Minimization for Ptychographic Phase Retrieval | |||
|- | |- | ||
| | |04/11 | ||
| | |903 | ||
| | |Ian McPherson | ||
|Convergence Rates for Riemannian Proximal Bundle Methods | |||
|- | |- | ||
| | |04/18 | ||
|9th floor | |||
|Weidong Ma | |||
|A topic in kernel based indepedence testing | |||
| | |||
| | |||
| | |||
|} | |} | ||
==Abstracts== | |||
'''March 7th, Ang Li (UW-Madison)''': I will share my experience with postdoc and industry job applications. This talk might be helpful for those who haven’t decided between academia and industry or are considering different paths within industry since I made my own decision quite late. | |||
'''April 4th, Borong Zhang (UW-Madison)''': In this talk, we introduce a novel stochastic multigrid minimization method designed for ptychographic phase retrieval. By reformulating the inverse problem as the iterative minimization of a quadratic surrogate that majorizes the original objective function, our approach unifies a range of iterative algorithms, including first-order methods and the well-known Ptychographic Iterative Engine (PIE). By efficiently solving the surrogate problem using a multigrid method, our method delivers significant improvements in both convergence speed and reconstruction quality compared to conventional PIE techniques. | |||
'''April 11th, Ian McPherson (Johns-Hopkins):''' Nonsmooth convex optimization is a classically studied regime with a plethora of different optimization algorithms being developed in order to solve them. Of these methods, proximal bundle methods have been created and used within the Euclidean setting for decades - attempting to mimic the dynamics of the proximal point method. While practitioners have enjoyed very robust convergence results with respect to choice of parameters, it was not until the late 2020s that we have had theoretical results giving non-asymptotic guarantees - recovering optimal convergence rates. Within the past few years, the first Riemannian Proximal Bundle Methods have been proposed, again lacking non-asymptotic guarantees. Within this talk, we discuss how we are able to both generalize proposed methods and lift the non-asymptotic rates to the Riemannian setting. Moreover, we will do so without access to exponential maps or parallel transports. In addition, to our knowledge these are the first theoretical guarantees for non-smooth geodesically convex optimization in the Riemannian setting, without access to either exponential maps and parallel transports. The work presented is joint work with Mateo Diaz and Benjamin Grimmer. | |||
== Past Semesters == | '''April 18th, Weidong Ma (Univeristy of Pennsylvania)''': | ||
==Past Semesters== | |||
*[[SIAM Seminar Fall 2024|Fall 2024]] | |||
*[https://wiki.math.wisc.edu/index.php/SIAM_Spring_2024 Spring 2024] | |||
*[[SIAM Fall 2023|Fall 2023]] | |||
*[[SIAM Spring 2023|Spring 2023]] | |||
*[[SIAM Seminar Fall 2022|Fall 2022]] | |||
*[[Spring 2022 SIAM|Spring 2022]] | |||
*[[SIAM Student Chapter Seminar/Fall2021|Fall 2021]] | |||
*[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]] | *[[SIAM_Student_Chapter_Seminar/Fall2020|Fall 2020]] | ||
*[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]] | *[[SIAM_Student_Chapter_Seminar/Spring2020|Spring 2020]] | ||
Latest revision as of 21:56, 9 April 2025
- When: Fridays at 1:30 PM unless noted otherwise
- Where: 9th floor lounge (we will also broadcast the virtual talks on the 9th floor lounge with refreshments)
- Organizers: Yahui Qu, Peiyi Chen and Zaidan Wu
- Faculty advisers: Jean-Luc Thiffeault, Steve Wright
- To join the SIAM Chapter mailing list: email siam-chapter+join@g-groups.wisc.edu.
- Zoom link: https://uwmadison.zoom.us/j/97976615799?pwd=U2xFSERIcnR6M1Y1czRmTjQ1bTFJQT09
- Passcode: 281031
Spring 2025
| Date | Location | Speaker | Title |
| 03/07 | 9th floor | Ang Li | Applying for postdocs and different industry jobs ... at the
same time |
| 04/04 | 9th floor | Borong Zhang | Stochastic Multigrid Minimization for Ptychographic Phase Retrieval |
| 04/11 | 903 | Ian McPherson | Convergence Rates for Riemannian Proximal Bundle Methods |
| 04/18 | 9th floor | Weidong Ma | A topic in kernel based indepedence testing |
Abstracts
March 7th, Ang Li (UW-Madison): I will share my experience with postdoc and industry job applications. This talk might be helpful for those who haven’t decided between academia and industry or are considering different paths within industry since I made my own decision quite late.
April 4th, Borong Zhang (UW-Madison): In this talk, we introduce a novel stochastic multigrid minimization method designed for ptychographic phase retrieval. By reformulating the inverse problem as the iterative minimization of a quadratic surrogate that majorizes the original objective function, our approach unifies a range of iterative algorithms, including first-order methods and the well-known Ptychographic Iterative Engine (PIE). By efficiently solving the surrogate problem using a multigrid method, our method delivers significant improvements in both convergence speed and reconstruction quality compared to conventional PIE techniques.
April 11th, Ian McPherson (Johns-Hopkins): Nonsmooth convex optimization is a classically studied regime with a plethora of different optimization algorithms being developed in order to solve them. Of these methods, proximal bundle methods have been created and used within the Euclidean setting for decades - attempting to mimic the dynamics of the proximal point method. While practitioners have enjoyed very robust convergence results with respect to choice of parameters, it was not until the late 2020s that we have had theoretical results giving non-asymptotic guarantees - recovering optimal convergence rates. Within the past few years, the first Riemannian Proximal Bundle Methods have been proposed, again lacking non-asymptotic guarantees. Within this talk, we discuss how we are able to both generalize proposed methods and lift the non-asymptotic rates to the Riemannian setting. Moreover, we will do so without access to exponential maps or parallel transports. In addition, to our knowledge these are the first theoretical guarantees for non-smooth geodesically convex optimization in the Riemannian setting, without access to either exponential maps and parallel transports. The work presented is joint work with Mateo Diaz and Benjamin Grimmer.
April 18th, Weidong Ma (Univeristy of Pennsylvania):