Thread: Stop infinity!
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Default 02-17-2007, 08:58 AM

Hello Dr. Jim,

Alice is a cross-platform programming environment, so the answer to that question depends on the platform -- both the specific operating system and the hardware, particularly the I/O hardware. Alice uses features in the programming languages used to create the Alice system, which in turn rely on features of the operating system, some of which rely on the hardware.

I did a few experiments with Alice on a Windows XP PC with a 3.0 Ghz processor and 1Gb of RAM, and found that Alice was responding to changes in the state of a Boolean variable in an average of about .015 seconds. I added ten objects to the world with separate events to keep each of them moving, and found that the results were the same. As far as I could tell, the presence of ten moving objects and ten additional events had no measurable effect on the time it took Alice to respond to the changes in state of a Boolean variable. At some point, perhaps when most of the memory is used up, the number of objects and events should affect response time. Responses time wil probably degrade with complicated texture maps and longer sound files added to a world.

I did notice that there is a pasue of about 1/3 of a second seconds when the the world first starts with the ten objects and ten events added. After that initial "time burp", the response times were the same with or without the added objects and events.

The fastest that someone can “tap” a key -- press the key and let go, is in the magnitude of 1/10th of a second. With modern CPU cycles in billionths of a second, even a million cycles takes less time than that. A rough answer is to your question is that Alice events seems to be fast enough so that other factors will constrict its response to events.

This doesn’t answer your question in terms of graphics refresh cycles, but it may help.
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