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DrawGraphics Figure-8 && CPU Strangeness
In a sense this problem gives me an excuse to call attention to one of the best uses I've seen a computer put to. The figure-8 Animation in David Park's DrawGraphics package is exactly the kind of graphical expression of the mathematics of physics which reviel more about the situation than pencile and paper lend themselves to. (People such as John A. Wheeler, and Hermann Weyl seem to have this kind of mechanism build into thier brains, and therefore don't need no stinkin' computer.) This is on SuSE Linux 8.1, P4/w 1 GIG of RAM. While I was exploring this animation I noticed something rather strange about the CPU's behavior. If I open Help Browser -> Add-Ons -> DrawGraphics -> Examples -> Figure Eight Animation, the CPU utilization is virtually 0. I evaluate the first cell to load the package and the CPU jumps for a second and then settles back down. I then select the remainder of the notebook. The CPU utilization remains very low. Then I evaluate it. The CPU utilization jumps way up, as is to be expected. The animation frames are created, and the animation runs fine. The CPU utilization remains very high. The interesting observation comes when I stop the animation by quitting the local kernel. If I select the cell holding the graphic, I notice the CPU utilization jups to 98%+-. The kernel isn't even running at this time. When I say I select the cell holding the graphic, I mean to say I select the brace to the right which has the 'foldable' indicator. Selecting the inner-most brace does not cause the CPU utilization to increase, but selecting any of its parents does. Can someone explain this? You can find the DrawGraphics package here: http://home.earthlink.net/~djmp/Mathematica.html -- STH Hatton's Law: "There is only One inviolable Law."