Another Word For It Patrick Durusau on Topic Maps and Semantic Diversity

August 17, 2012

A CS Intro Do-Over?

Filed under: CS Lectures — Patrick Durusau @ 11:01 am

Intro Curriculum Update

Robert Harper describes (in part) the CS introduction “do-over” at Carnegie Mellon:

In previous posts I have talked about the new introductory CS curriculum under development at Carnegie Mellon. After a year or so of planning, we began to roll out the new curriculum in the Spring of 2011, and have by now completed the transition. As mentioned previously, the main purpose is to bring the introductory sequence up to date, with particular emphasis on introducing parallelism and verification. A secondary purpose was to restore the focus on computing fundamentals, and correct the drift towards complex application frameworks that offer the students little sense of what is really going on. (The poster child was a star student who admitted that, although she had built a web crawler the previous semester, she in fact has no idea how to build a web crawler.) A particular problem is that what should have been a grounding in the fundamentals of algorithms and data structures turned into an exercise in bureaucratic object-oriented nonsense, swamping the core content with piles of methodology of dubious value to beginning students. (There is a new, separate, upper-division course on oo methodology for students interested in this topic.) A third purpose was to level the playing field, so that students who had learned about programming on the street were equally as challenged, if not more so, than students without much or any such experience. One consequence would be to reduce the concomitant bias against women entering CS, many fewer of whom having prior computing experience than the men.

The solution was a complete do-over, jettisoning the traditional course completely, and starting from scratch. The most important decision was to emphasize functional programming right from the start, and to build on this foundation for teaching data structures and algorithms. Not only does FP provide a much more natural starting point for teaching programming, it is infinitely more amenable to rigorous verification, and provides a natural model for parallel computation. Every student comes to university knowing some algebra, and they are therefore familiar with the idea of computing by calculation (after all, the word algebra derives from the Arabic al jabr, meaning system of calculation). Functional programming is a generalization of algebra, with a richer variety of data structures and a richer set of primitives, so we can build on that foundation. It is critically important that variables in FP are, in fact, mathematical variables, and not some distorted facsimile thereof, so all of their mathematical intuitions are directly applicable. So we can immediately begin discussing verification as a natural part of programming, using principles such as mathematical induction and equational reasoning to guide their thinking. Moreover, there are natural concepts of sequential time complexity, given by the number of steps required to calculate an answer, and parallel time complexity, given by the data dependencies in a computation (often made manifest by the occurrences of variables). These central concepts are introduced in the first week, and amplified throughout the semester.

Competing CS courses present an unprecedented opportunity to compare and contrast teaching of CS materials.

And, opportunity to capture (and map) vocabulary shifts in the discipline.

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