Diff: ArithmeticEncoding

Differences between current version and predecessor to the previous major change of ArithmeticEncoding.

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Newer page: version 2 Last edited on Friday, October 10, 2003 12:35:03 am by StuartYeates
Older page: version 1 Last edited on Monday, September 1, 2003 9:07:56 am by GreigMcGill Revert
@@ -1,4 +1,10 @@
-An arithmetic encoder takes a string of symbols as input and produces a rational number in the interval [,1) as output . As each symbol is processed, the encoder will restrict the output to a smaller interval
+An encoding of all binary strings in the range to all [Binary] strings in the domain, based on an expected probability distribution of bitstings. The encoder starts with the range [,1) and to encode reach bit the encoder takes the expected distribution of the bit (maybe 20/80) and divides the range in those proportions and throws away the portion the bit didn't fall into (in this case either [ [,.2) or [[.8 ,1) ) . When all bits have been seen the range is sent as the encoding
-Note: Cut and Pasted definition . Someone with a math background might like to AddToMe. 
+ArithmeticDecoding is the reverse process .  
+ArithmeticEncoding has been shown to be the asymototical optimal way to encode such a string (only asymototical optimal because of the need to round up the range to the nearest bit).  
+ArithmeticEncoding and ArithmeticDecoding are used in bzip2(1) and but zip(1).  
+ AddToMe.