Gauss-Jordan elimination in Excel/VBA. The use of matrix problems in Informatics II class

In our undergraduate Informatics II: VBA for non-IT students, class we do many computations on matrices – in order to let students reason algorithmically. As we start out, it’s good to show that a simple 12 row algorithm can solve linear equation systems by doing Gauss-Jordan elimination. Examples of subsequent test problems include: finding the number of elements between -3 and +3 amongst those above the main diagonal; finding the average of all positive elements of a matrix.

As a huge variety of such problems can be created, this is a topic that guarantees a thorough and genuine understanding of the code written – compared to other topics of the class, where a bigger proportion of material seems to be memorized, and not so thoroughly understood. This topic also gives a good incentive for streamlining testing – as literally hundreds problems can be handed out as WebCT tests; with students entering the multiple choice (again from amongst hundreds) answers after doing programming in Excel/VBA. In order to be sure of students’ comprehension of the topic, multiple tests have to be completed.