Algorithm: A Ninth-Century Term for 21st-Century Computing


Computer scientist Thomas Cormen still remembers that he “only got an A minus” in his algorithms course at Princeton. This minor blemish on his academic record didn’t stop Cormen, a New Yorker, from graduating summa cum laude and Phi Beta Kappa. Curiously, it turns out that much of his professional life has revolved around the science of algorithms.

Professor Tom Cormen in his office

Thomas Cormen is a professor and chair of the Department of Computer Science, and a specialist on the subject of algorithms. (Photo by Eli Burakian)

Whether we know it or not, our lives revolve around algorithms. Much of what we do today depends on computers, and algorithms are the step-by-step sets of instructions a computer must follow in order to do its job.

“Algorithms are at the core of all things digital,” says Cormen, a professor and chair of Dartmouth’s Department of Computer Science. “They run on your laptop, your smartphone, your GPS device, and in systems imbedded in your car, your microwave oven—everywhere.”

While algorithms are everywhere, the word does not roll smoothly off the tongue. It is a word deeply rooted in history, a corruption of the name al-Khwarizmi, a ninth-century Persian mathematician, astronomer, and geographer renowned for his treatise on algebra—another word attributed to him.

Cormen’s own history of involvement with algorithms continued in his graduate studies at the Massachusetts Institute of Technology (MIT). He was a teaching assistant for his research adviser, Professor of Computer Science and Engineering Charles Leiserson. Cormen was assigned the task of writing up Leiserson’s lecture notes for the undergraduate algorithms class and then distributing them to the students. Cormen recalls, “At the end of the term, Leiserson said to me, ‘You did a great job. How about we turn these into a book?’ ”

In the tradition of “no good deed goes unpunished,” Cormen took on the job and for the next three-and-a-half years worked with Leiserson on what turned out to be Introduction to Algorithms, the 1,050-page classic textbook on the subject, now in its third edition.Turing Award winner Ronald Rivest of MIT was a co-author on the first edition and Clifford Stein of Columbia University joined the team for the second edition.

In March, 2013, Cormen published his latest work, Algorithms Unlocked“I wanted to write something shorter, a book that someone with really minimal background in computer science could pick up and understand,” says Cormen. He hoped that readers of the new book would be motivated to explore the big book—the behemoth Introduction to Algorithms. “What I am finding, at least when I look at reviews online, is that it seems to be the other way around. People have read Introduction to Algorithms, and then they are reading this to see what they missed.”

cover of Tom Cormen's book Algorithms Unlocked

“Algorithms Unlocked,” Thomas Cormen’s newest book, is a guide to the basics of computer algorithms.

Cormen has taught Dartmouth’s introductory course in computer science for 19 of the 21 years he’s been at the College. “I love teaching this course because I really like getting students hooked on computer science,” he says. “I love it when there is a student who was not planning to study computer science takes this course and it changes their life.”

Among his pedagogical pursuits, Cormen teaches a graduate course on how to write papers and give presentations. Having served as the director of the Dartmouth College Writing Program (now the Institute for Writing and Rhetoric) from 2004-2008, he brings his communication skills to the more arcane precinct of computer science.

“I take examples that you would find in the bookStyle: The Basics of Clarity and Grace, and modify them to use computer science terms. That book starts out with a bad sentence, diagnoses it, shows you how to fix it, and make it a much better sentence,” Cormen explains. After substituting computer science nouns and verbs in the “bad sentence,” he says, “it looks just like the stuff we read in academic journals—almost incomprehensible—so this gives the students good motivation to improve their writing.” The course also includes a unit on presentations—how to give talks.

As department chair, Cormen has encouraged the recruitment of more women into the field. Cormen has also been a strong supporter of Women in Computer Science, a club recognized by the Dartmouth’s Council on Student Organizations.

Cormen is in the first year of his second three-year term as department chair and, while his administrative chores have cut into his research time, he says accomplishments in other areas tend to balance out his paucity of new research papers.

“With research, what you are hoping to do is make an impact on the world. What I am hoping to do as an administrator is make more of an impact on Dartmouth by doing everything I can to help this department,” he says.

Cormen has initiated a lot of renovations in Sudikoff Laboratory “to try to make the building better for research and for teaching. We are renovating two of the undergraduate labs this summer and we’ve done most of the seminar rooms, replacing projectors by 55-inch flat-screen TVs for presentations.

“My approach as a chair is to get the resources that our faculty and students need, and deploy those resources to enable them to do their work.”

Joseph Blumberg