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Recalling Saylor's Impact Begins with Numerical Analysis, Continues with Human Connections

12/17/2020 9:31:49 AM Aaron Seidlitz, Illinois CS

The impact of Paul Saylor’s 34-year career as a professor with Illinois CS (1967-2001) remains crystal clear, because of the influence he had both professionally and personally with former students and colleagues.

Professor Emeritus Paul Saylor
Former CS faculty member Paul Saylor passed away November 7, 2020.

After learning of the 81-year old Saylor’s death on November 7, those same students and colleagues recalled what he meant to them. He was a man fiercely dedicated to constant learning within his field of choice. Saylor's passion for numerical analysis and computational science led to personal connections that lasted a lifetime. Those relationships only strengthened as others realized his zeal for learning equated only to his powerful devotion to help those he cared about.

One such former student, Steven Ashby (PhD CS ’87), couldn’t help but think back on the “small nudges” he received in life – none more important than a purposeful introduction to Saylor.

Before his graduate studies at Illinois CS, Ashby was as an undergraduate student more than 2,000 miles away at Santa Clara University. Despite the distance, one day, there was a professor from the University of Illinois at Urbana-Champaign outside his classroom waiting to meet him.

He took the meeting and learned that Saylor wanted him to continue his studies in math and computer science at Illinois. The doctorate program would offer him a chance to progress in a way Ashby hadn’t considered.

Instead of going out into the workforce near his home, he moved the furthest east he’d ever lived to Illinois’ flat cornfields. He trusted in Saylor, much like he had trusted the undergraduate advisers that steered him toward math and computer science in the first place.

That trust led him through the masters and PhD programs in CS at Illinois. And his relationship with Saylor paved the way for several introductions to influential people with similar interests at national laboratories across the United States.

That trust led to Ashby’s career development in the laboratory setting. First, there was a 21-year span with Lawrence Livermore National Laboratory, where he founded the laboratory’s Center for Applied Scientific Computing, one of the world’s premier scientific computing research organizations. Currently, he is the Director of the Pacific Northwest National Laboratory.

“I’ve reflected many times on the small nudges you get in life. It may be the hand of God tapping on your shoulder or people intervening,” Ashby said. “Every so often somebody would say it’s luck. I never believed that, though. I believe that if you listen, you can find people who have the advice that will shape your life.

“Paul always gave me great advice.”

Saylor’s own nudge to Illinois came after a BS from Stanford University, his MS from University of Texas at Austin and a PhD at Rice University.

Illinois had already made a name with the ILLIAC series of computers, dating back to the 1950s. In 1965, a year after the Digital Computer Laboratory was reorganized into the Department of Computer Science, work began on the massively parallel ILLIAC IV, which later became the fastest supercomputer in the world after it became fully operational in 1975.

Saylor joined the faculty at Illinois in 1967, as the ILLIAC IV group recognized the need for a numerical analyst – a remarkable opportunity for the young scientist.

“We can attribute the long history of successful numerical analysis at Illinois CS to Paul. He joined the department at the same time the ILLIAC IV project needed a numerical analyst. Then he and his students laid a groundwork in this area that we still rely upon for methods we currently use," said Luke Olson, professor and Willett Faculty Scholar.

Saylor in his classroom, circa 1969.
Saylor in his classroom, circa 1969.

Over time, Saylor continued to display expertise in scientific computing and numerical analysis.

"Numerical analysis at Illinois is legendary, and Paul Saylor is, in large part, the reason why," said Nancy M. Amato (PhD CS '95), Illinois CS Department Head and Abel Bliss Professor of Engineering. "We are one of the few computer science programs that includes numerical analysis as a core part of the department—most often it is in mathematics departments.

"This started with Paul and the fact that we continue to have a premier numerical computing program and faculty today at Illinois is part of Paul's lasting legacy."

Saylor focused on projects that approximated solutions to systems of partial differential equations arising through scientific study.

He worked extensively with engineers and scientists to develop iterative approaches for problems where it is difficult to efficiently obtain precise solutions using direct methods. Saylor's equations could calculate error and minimize its effect through an iterative process.

Saylor’s enhancements to iterative methods have led to more precise solutions and improvements in many different fields, including aeronautics, medical imaging, electromagnetics, groundwater hydrology, oil reservoir detection and general relativity.

Saylor loved finding a similar motivation in students, and then matching them up with collaborators to make a difference.

His ability to do so sparked a connection between Ed Seidel – current president at the University of Wyoming and former director of the National Center for Supercomputing Applications (NCSA) at Illinois – and PhD student Steven Lee (PhD CS ’93).

Their collaboration helped pave the way for an eventual breakthrough.

In 2017, the National Science Foundation announced that scientists had, for the first time, “observed ripples in the fabric of spacetime called gravitational waves.” This discovery built upon a century’s worth of study, dating back to Albert Einstein’s 1915 general theory of relativity.

As a research scientist at NCSA in the early 1990s, Seidel focused on solving Einstein’s equations, specifically looking at the black hole and gravitational wave problems. Lee was doing his doctoral research on equations that were able to conserve certain constraints, such as conservation of mass or of momentum. His work dovetailed nicely with the physics work that Seidel was doing at NCSA.

“There are now more sophisticated methods,” Seidel explained at the time of the discovery. “I don’t want to say that they are using the methods that we developed. But we did do—in collaboration with Paul—the first three-dimensional collisions of black holes and wave forms from them. Those were stepping stones along the way.”

Together with Saylor, Lee met regularly with Seidel’s NCSA team to develop new approaches.

“I believe that Paul was instrumental in terms of connecting the dots [for] getting the top computational scientists interested in this problem,” said Lee in a 2016 interview, noting that these connections developed important interactions across science fields. “It was a new degree of collaborating among mathematicians and computer scientists and physicists—people who were studying general relativity.”

The experience also proved as one more example of Saylor’s dedication to his craft.

“Paul has written the book, figuratively and literally, on applied mathematics and iterative methods," Seidel said. “His influence on me touched many aspects of my life. In fact, Paul described life to me as an iterative method. He said that every action we take creates an error. We hope that over time, and with more work, the errors will decrease.”

Beyond Saylor's academic purpose, there was a human connection the professor made with his students.

After moving halfway across the country to attend Illinois CS, Ashby said he became a member of the Saylor family – such was life when you were around Paul and his wife, Cynthia.

The Saylor children, Gerrit and Gerard, were young at the time. Ashby often found himself at his adviser's home, invited over for dinner or a visit. He watched the children grow up amidst laughter and intellectual curiosity.

Paul Saylor, circa 2000.
Paul Saylor, circa 2000.

“What made it such a warm and positive experience for me was the Saylor family and Paul’s guidance,” Ashby said. “Their welcoming embrace and heartfelt kindness sustained me when I wasn’t near my family for the first time in my life. That relationship never changed, even after graduation. For example, Paul and my future wife’s PhD adviser conspired to arrange our introduction at a math conference.”

His dedication to research and teaching earned Saylor the 2015 Distinguished Academic Achievement Alumni Award. His enduring friendship with Gene H. Golub (B.S. Mathematics ’53; M.A. Mathematical Statistics ’54; PhD Mathematics ‘59) led to the Paul and Cynthia Saylor Professorship in Computer Science, established in 2005.

"Our long history of leadership in scientific and parallel computing is also tied to our strength in numerical analysis, which, again, was all strongly influenced by Paul Saylor. This is as true today as it was when I was a grad student here more than two decades ago.  We miss Paul, but we are surely never going to forget him and his contributions to the field and the department," Amato said.

After retiring from the university in 2001, Saylor held positions with the National Science Foundation as program director for computational mathematics and at Louisiana State University Center for Computation and Technology as visiting professor. He served as principal investigator for the NASA Earth and Space Grand Challenge on Simulating the Merger of Binary Neutron Stars, as well. Saylor also continued consulting work with several national laboratories.

Saylor is survived by wife Cynthia; his sons, Gerrit of Seattle and Gerard of Lake Mills, Wis.; grandsons, Quentin and Ian; brother, Doyle; nephews, Andrew and John Kenner; honorary family member, Ivor Brown; and many devoted doctoral students.

Memorial contributions can be made to the Paul Saylor Fellowship in Scientific Computing.