22 lines
345 B
Forth
22 lines
345 B
Forth
: flog2 ( f -- f ) fln 2e fln f/ ;
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create freq 256 cells allot
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: entropy ( str len -- f )
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freq 256 cells erase
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tuck
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bounds do
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i c@ cells freq +
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1 swap +!
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loop
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0e
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256 0 do
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i cells freq + @ ?dup if
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s>f dup s>f f/
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fdup flog2 f* f-
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then
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loop
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drop ;
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s" 1223334444" entropy f. \ 1.84643934467102 ok
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