ACM SIGAPL APL Quote Quad

Reiter, Cliff

doi: 10.1145/1354923.1354924pmid: N/A

Computational exercises and demonstrations appear frequently in the classes that I teach at Lafayette College. The software that I use for in-class demonstrations is usually Mathematica 4 or J 3. I focus on one language or the other throughout the course when I expect the students to develop the ability to make substantial explorations and do independent experimentation. There is an ongoing expectation at Lafayette that Mathematica be used in Calculus Classes 2; I also use Mathematica for my Numerical Analysis and Techniques of Math Modeling classes. I use J for teaching Number Theory and Linear Algebra and it is central to my mathematical visualization course that follows the text 6. However, I always have interest in how the explorations that I do in one language would be done in the other.

Kutinsky, Vladimir

doi: 10.1145/1354923.1354925pmid: N/A

This article covers the problem of making client requests to Web servers over HTTP. More specifically, this article addresses two interrelated problems, sending data to a Web server using the POST method and processing the request with a CGI script at the server side. The purpose of this work is to provide a basis for understanding how these tasks can be performed in APL. While the proposed solutions are of a general form, the discussion is oriented around working examples, instead of simply providing reference material. The APL code discussed in the article uses a number of .Net libraries that greatly assist the task of programming and do most of the drudgery work for us, hence the name of the article.

Alfonseca, Manuel

doi: 10.1145/1354923.1354926pmid: N/A

This paper describes the use of grammatical evolution to generate APL programs which perform some pre-required function.

Polivka, Ray

doi: 10.1145/1354923.1354927pmid: N/A

The answer to the sums of the diagonals of a 1001 by 1001 spiral matrix is 669,171,001. More interesting than the answer is the number of responses and the variety of solutions. Beside solutions from APL and J, I received solutions using C++, RoboBasic, and EXCEL. Several submitters used their observations to produce mathematical solutions. Some of the mathematical solutions resulted in different equations. I'll try to summarize all the submissions.

Polivka, Ray

doi: 10.1145/1354923.1354928pmid: N/A

Let us have some fun selecting out diagonals from rank 2 and 3 arrays. It is really an exercise in using some of the lesser-used but powerful primitive APL functions. There are probably several ways to arrive at the solutions. Let's see what we get.

Fornallaz, Andrew W.

doi: 10.1145/1354923.1354929pmid: N/A

This paper refers to the section Exercises and Problems, published in the September 2007 APL Quote Quad issue, Volume 35, Number 3, and to the problem Diagonal Sums on Spiral Matrices, proposed by Ray Polivka.