<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">DEPARTMENT OF COMPUTER SCIENCE - TALK </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><br class="khtml-block-placeholder"></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">SPONSORED BY UNIVERSITY OF CHICAGO</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Date: Friday, February 8, 2008</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Time: 2:30 p.m.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Place: Ryerson 251, 1100 E. 58th St.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal Helvetica; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">-------------------------------------------</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><br class="webkit-block-placeholder"></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" color="#272727">Speaker: Jianlin Xia</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" color="#272727"><br></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" color="#272727">From:</font><span class="Apple-tab-span" style="white-space:pre"><font class="Apple-style-span" color="#272727"> </font></span><font class="Apple-style-span" color="#272727">University of California - Los Angeles</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" color="#272727"><br class="webkit-block-placeholder"></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" color="#272727">Web page: </font><a href="http://lmi.bwh.harvard.edu/~gk/"><font class="Apple-style-span" color="#272727">http://www.math.uchla.edu/~jxia/</font></a></div>
<!--StartFragment-->
<!--EndFragment-->
<div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" color="#272727"><br class="webkit-block-placeholder"></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span style=""><font class="Apple-style-span" color="#272727">Title:</font></span><span style=""><font class="Apple-style-span" color="#272727"> </font><span class="Apple-style-span" style="font-weight: bold; "><font class="Apple-style-span" color="#272727">"Superfast solvers for some large structured matrix problems"</font></span></span></div>
<!--StartFragment--><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">
<div class="MsoNormal"><span style=""><font class="Apple-style-span" color="#272727"> </font><font class="Apple-style-span" color="#272727"><o:p></o:p></font></span></div><p class="MsoNormal" style="mso-pagination:none;mso-layout-grid-align:none;
text-autospace:none"><font class="Apple-style-span" color="#272727">Abstract: "This talk discusses superfast solvers for some large matrix problems which are rank structured. Examples of these structured problems include some large discretized PDEs, Toeplitz systems, certain low-rank updated eigenproblems (e.g. companion matrices), and others. Our superfast solvers use certain semiseparable rank structured matrices. I will first briefly show an example of a quadratic cost companion matrix eigensolver and condition estimator. Then I will focus on a fast multifrontal type direct solver for large sparse discretized PDEs. Mesh ordering and node elimination schemes are discussed. Semiseparable matrices are used to approximate dense intermediate matrices in the factorization. A new linear time factorization algorithm for semiseparable matrices is presented. The overall sparse solver has nearly linear complexity and linear storage, and has good potential for parallelization. It can also work as an effective preconditioner. Numerical results will be shown. This is joint work with Shiv Chandrasekaran, Ming Gu, Alan Laub, and Xiaoye Li."</font></p>
<!--StartFragment-->
<!--EndFragment-->
<p class="MsoNormal" style="mso-pagination:none;tab-stops:28.0pt 56.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt;
mso-layout-grid-align:none;text-autospace:none"><span style="color: black; "> ****************************<o:p></o:p></span></p><p class="MsoNormal" style="mso-pagination:none;tab-stops:28.0pt 56.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt;
mso-layout-grid-align:none;text-autospace:none">Host: Todd Dupont</p><p class="MsoNormal" style="mso-pagination:none;tab-stops:28.0pt 56.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt;
mso-layout-grid-align:none;text-autospace:none"><br class="webkit-block-placeholder"></p><p class="MsoNormal" style="mso-pagination:none;tab-stops:28.0pt 56.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt;
mso-layout-grid-align:none;text-autospace:none"><br class="webkit-block-placeholder"></p><p class="MsoNormal" style="mso-pagination:none;tab-stops:28.0pt 56.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt;
mso-layout-grid-align:none;text-autospace:none">***********************************************************************************************************************************</p>
<!--EndFragment-->
</div><div> <span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Nita</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; min-height: 14.0px"><br></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">**************************</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Nita Yack</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Departmental Administrator</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Computer Science Department</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">1100 E. 58th Street - Room 151</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Chicago, IL 60637</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">(773) 702-6019</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">(773) 702-8487 FAX</font></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><br class="khtml-block-placeholder"></p><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font class="Apple-style-span" face="Arial" size="4"><span class="Apple-style-span" style="font-size: 16px;; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 16px; "><span class="Apple-style-span" style="font-family: Arial; font-size: 16px; ">"Hard work spotlights the character of people: some turn up their </span></span></span></font><font class="Apple-style-span" face="Arial" size="4"><span class="Apple-style-span" style="font-size: 16px;; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 16px; "><span class="Apple-style-span" style="font-family: Arial; font-size: 16px; ">sleeves, some turn up their noses, and </span></span></span></font><font class="Apple-style-span" face="Arial" size="4"><span class="Apple-style-span" style="font-size: 16px;; font-family: Arial; "><span class="Apple-style-span" style="font-family: Arial; font-size: 16px; "><span class="Apple-style-span" style="font-family: Arial; font-size: 16px; ">some don't turn up at all."</span></span></span></font></p><br class="Apple-interchange-newline"></span></div></span> </div><br></body></html>