Re: BitSet vs BigInteger (false Android doc)
On 9/3/2011 4:46 PM, Jan Burse wrote:
Patricia Shanahan schrieb:
It uses a NativeBN implementation, which appears from various comments
and fields to be sign-and-magnitude based, not 2's complement. The bit
manipulation methods use a method prepareJavaRepresentation that I think
converts to 2's complement.
I don't see how the 1's complement influences the BigInteger performance
when we compare with BitSet. BitSet can only represent what corresponds
to positive numbers in BigInteger.
But still I don't think that the Android comment covers the current
state of affairs. Since it explicitly refers to BitSet, and BitSet
and BigInteger are the same on the common domain of positive integers.
BitSet is not in the domain of integers at all.
The BigInteger API has methods for converting between internal
representation and bytes in two complements. It should be obvious
that at least code that uses that feature will carry overhead
for an implementation not using two;s complement.
Arne
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