Wolfram Computation Meets Knowledge

Date Archive: 2011 April


And the Winners Are…

The Wolfram Demonstrations Challenge has run its course, and you have participated in droves. It's time to pick the winners. We do things our own way at Wolfram Research. We don't pull slips of paper from a hat or ping-pong balls from a barrel for prize drawings. We write Mathematica programs to tell us who the winners are. Of course. I wrote the program, but not wanting to expose myself to accusations of improperly influencing my laptop, I didn't run it myself. Stephen Wolfram did and sent me the results. And the winners are...

Mathematica Q&A: Sow, Reap, and Parallel Programming

Got questions about Mathematica? The Wolfram Blog has answers! We'll regularly answer selected questions from users around the web. You can submit your question directly to the Q&A Team using this form. This week's question comes from Patrick, a student: How can I use Sow & Reap across parallel kernels? Before we answer this question, a review of the useful functions Sow and Reap is in order. Sow and Reap are used together to build up a list of results during a computation. Sow[expr] puts expr aside to be collected later. Reap collects these and returns a list: The first part of the list is the regular result of the computation. The second part is everything that was “sown”. Sow and Reap are ideally suited to situations in which you don't know in advance how many results you will get. For example, suppose that you want to find simple initial conditions that lead to "interesting" results in Conway's game of life, the famous two-dimensional cellular automaton:

Announcing the Wolfram Demonstrations Challenge

As a long-time developer at Wolfram Research, I can attest that the job requires superhuman discipline and self-control. Those who lack fortitude are soon undone by the irresistible functionality we build into Mathematica and spend their days exploring the esoteric topics they've always wondered about instead of building more great technology. The situation has recently gotten worse.