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Re: [aima-talk] search/domain/vacuum.lisp source code "rotate" function

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  • Peter Norvig
    The theory is vector arithmetic. If you work out the combinations, it turns out the same as what you would be doing in your enumeration of cases. -Peter
    Message 1 of 2 , Dec 1, 2003
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      The theory is vector arithmetic. If you work out the combinations, it
      turns out the same as what you would be doing in your enumeration of
      cases.

      -Peter Norvig

      On Sunday, November 30, 2003, at 06:33 PM, chenyu468 wrote:

      > Hi everyone,
      > I have read "vacuum.lisp", "utility.lisp" source code. The
      > function "rotate" in the "utility.lisp" make me puzzle.
      >
      > The purpose of "rotate" function is to change the "oriention" of
      > vacuum depends on the "current orientation" and "change requirement,
      > for example 'left', 'right'".
      >
      > If I wrote this function ("rotate"), I would use the enumeration
      > method to solve the problem, that's, combination of 4 possible ((1 0)
      > (-1 0) (0 1) (0 -1))orientation and 2 possible change ("left"
      > or "right").
      >
      > But the author ( Mr.Norvig or Mr. Russel) has solve the problem by
      > algebra operation which is more elegant and abstract (just 2 possible
      > combination, not 8 possible combination). I like this method, but
      > don't know what's the theory details behind it. What's it, could you
      > help me?
      >
      > Thank you for your attention.
      > kind regards/chenyu
      >
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