16 lines
458 B
Factor
16 lines
458 B
Factor
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USING: kernel quotations sequences math math.vectors random ;
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IN: random-weighted
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: probabilities ( weights -- probabilities )
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dup sum [ / ] curry map ;
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: layers ( probabilities -- layers )
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dup length 1+ [ head ] curry* map 1 tail [ sum ] map ;
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: random-weighted ( weights -- elt )
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probabilities layers [ 1000 * ] map 1000 random [ > ] curry find drop ;
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: random-weighted* ( seq -- elt )
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dup [ second ] map swap [ first ] map random-weighted swap nth ;
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