Obituaries: Hans Petter Langtangen

By Xing Cai, Jan S. Hesthaven, Martin Peters, Marie E. Rognes, and Aslak Tveito

Professor Hans Petter Langtangen, a brilliant and beloved scientist and educator, passed away last October after an 18-month fight with cancer. Hans Petter’s research revolved around numerical methods and scientific software tools for continuum mechanical problems. His approach was truly interdisciplinary, combining mathematics, statistics, and computer science to address problems in physics, geoscience, physiology, and medicine. Hans Petter was an unusually inspirational and visionary man, always motivating colleagues and students with his enthusiasm, encouragement, inspiration, and insight. He will be deeply missed by all those who knew him.

Hans Petter was born on January 3, 1962, in Vinderen, a neighborhood in Oslo, Norway. He received his M.Sc. and Ph.D. degrees in mechanics from the Department of Mathematics at the University of Oslo in 1985 and 1989, respectively. Hans Petter’s research interests at the time encompassed computational methods for fluid flow, multiphase flows in porous media, and stochastic mechanics, topics that would follow him throughout his career.

Hans Petter started his career at Stiftelsen for industriell og teknisk forskning (SINTEF) in 1990, before becoming an assistant professor at the University of Oslo in 1991. Around that time, he began his groundbreaking work in applying C++ to implement partial differential equation solvers, which led to the renowned Diffpack library. Hans Petter was promoted to full professor of mechanics in 1998; he became a professor of scientific computing in the Department of Informatics in 1999.

In 2001, Hans Petter helped found Simula Research Laboratory, and remained a cornerstone of the research and educational environment there for several years. In 2007, he established the Center for Biomedical Computing (CBC), a Norwegian Centre of Excellence dedicated to the development and application of novel simulation technologies to better understand complex physiological processes affecting human health. At the CBC, Hans Petter continued his pivotal roles as a visionary driver and advocate for Python-based numerical software, in particular through the FEniCS Project, an open-source platform for automated scientific computing. In addition, he spearheaded the use of mathematical modelling and numerical simulation in new application areas associated with cardiovascular and neurological disorders, such as stroke and dementia.

Hans Petter was a singularly-talented, passionate, and much-beloved educator for over three decades. Since the early 2000s, he played a central role in the Computing in Science Education initiative at the University of Oslo. This project, which had wide international impact, revolutionized the integration of programming and simulation in mathematics and basic science education at the university. In 2016, Hans Petter received the Olav Thon Foundation Prize for Excellence in Teaching for his pioneering role and innovative methods in the teaching of programming and several other fields.

Hans Petter was a brilliant and prolific writer. He wrote a number of well-recognized books to accompany his courses, including A Primer on Scientific Programming with Python, which introduces programming via the Python language, and Computational Partial Differential Equations: Numerical Methods and Diffpack Programming, which teaches finite element methods to generations of students. His courses, ranging from introductory to graduate level, became the most popular courses in the Department of Informatics at the University of Oslo. Hans Petter supervised nearly 100 M.Sc./Ph.D. students, and was exceptionally dedicated to mentoring and advancing young researchers and scientists. He was an outstanding lecturer.

In addition to those that served as teaching material for his courses, Hans Petter authored several other books (he completed four during his last year), published upwards of 60 papers in international journals and over 60 peer-reviewed book chapters and conference papers, and gave more than 130 scientific presentations. He served as editor-in-chief of the SIAM Journal on Scientific Computing from 2011 to 2015, and was on the editorial boards of six other international journals. Hans Petter was also a member of the Norwegian Academy of Science and Letters and the European Academy of Science.

A conference on computational science and engineering in memory of Hans Petter is planned for October 23-25, 2017, in Oslo. In the meantime, condolences and tributes from friends and colleagues are welcome at his memorial page. As evidenced by these remembrances, Hans Petter and his warmth, enthusiasm, sense of humour, and drive left a mark on everyone he interacted with. Colleagues looked forward to even routine meetings with him; a serendipitous discussion with Hans Petter tended to brighten anyone’s day, and an email from him was a source of encouragement and inspiration. We will miss him deeply.

Xing Cai is a chief research scientist at Simula Research Laboratory in Norway and a professor of scientific computing at the University of Oslo. He is a former student of Hans Petter Langtangen at both the masters and doctoral levels. Jan S. Hesthaven is a professor of mathematics and Dean of Basic Sciences at the École Polytechnique Fédérale de Lausanne (EPFL) and currently serves as editor-in-chief of the SIAM Journal on Scientific Computing, succeeding Hans Petter. Martin Peters is executive editor of mathematics and computational science and engineering at Springer in Heidelberg, Germany. Marie E. Rognes is a chief research scientist at Simula Research Laboratory and a former student of Hans Petter at both masters and doctoral levels. Aslak Tveito is managing director of Simula Research Laboratory and a professor of scientific computing at the University of Oslo.