Dear Final Debug: I’ve been learning Mathematica. I’m a researcher and I’m using it to evaluate some pretty complicated rules. How can I control infinite evaluations without them going on forever and ever? — Rodney Plimpton, Chicago. Final Debug Responds: Rodney,Silicon Prairie will be covering Mathematica in detail later in the spring (it’s the program’s tenth anniversary), but we’ll try to answer your specific question, with some help from program author Stephen Wolfram’s The Mathematica Book. You’d think Mathematica would go into an infinite loop if you input an assignment such as x=x+1. But Mathematica doesn’t work that way. It does stop, and you can determine when. Check the global variable $RecursionLimit and set the maximum date of the evaluation stack, or edit $IterationLimit to set the maximum length of an evaluation chain. Next week we’ll return to the Internet, answering a question about streaming media options.
The contest might be in an infinite loop As of Wednesday morning, we’ve received 73 answers to our latest question. None of them are even remotely correct. So let’s try again. As you may recall, the first person who submits a correct answer will win a trio of books about Macromedia Director and a copy of Natrificial’s The Brain.The two-part question is:Name two capabilities that CDF files offer that Netcaster doesn’t — and two examples of Netcaster functionality you can’t get in CDF.If you know the answer, tell us already! If you want to submit a question, send it to us!
