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alexbowe/popcount_table.erl

Created April 4, 2011 07:01
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Generates a tuple of popcounts.
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popcount_table.erl
-module(popcount_table).
-export([gen_table/1]).
gen_table(Bits) -> gen_table(1, 2 bsl (Bits - 1), {0}).
gen_table(Stop, Stop, Table) -> Table;
gen_table(Value, Stop, Table) ->
New = (Value band 1) + erlang:element((Value bsr 1) + 1, Table),
NewTable = erlang:append_element(Table, New),
gen_table(Value + 1, Stop, NewTable).
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