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From "Daniel Fridlender" <dfridlen...@gmail.com>
Subject Re: ITC's java.math package contribution
Date Sun, 23 Apr 2006 00:01:20 GMT
Hi Geir,

We implemented BigDecimal using only public features of BigInteger, so
that our implementation of BigDecimal can be combined with any other
implementation of BigInteger.

On the other hand, having different internal representations would
make it hard to combine both implementations of BigInteger into a
single one.

But we would be very happy to include into our implementation
everything from HARMONY-39 that would enhance its performance.  We are
willing to continue optimizing our implementation further.

Regards,

Daniel Fridlender


On 4/21/06, Geir Magnusson Jr <geir@pobox.com> wrote:
> This is great stuff.  It will be fun to integrate all of this together
> to get the best of both.
>
> Now, with that happy and positive yet blatantly naive statement out there...
>
> How monolithic are these implementations?  Will it even be possible to
> integrate, or do the internals reflect enough difference in approach
> that it will be one or the  other?
>
> geir
>
>
> Semukhina, Elena V wrote:
> > Hi Daniel,
> >
> >
> >
> > I've taken a look at ITC's implementation of java.math (original
> > Harmony-199 donation) and tried to compare it to one donated by
> > Harmony-39 on the method-by-method base.
> >
> > For example, I've tested about 30 BigInteger's methods and the result is
> > the following:
> >
> >
> >
> > - 10 ITC's methods are slower,
> >
> > - 5 methods are approximately the same in both implementations,
> >
> > - 14 ITC's methods are faster.
> >
> >
> >
> > This is determined either by internal representation (which is different
> > in both implementations) or algorithmically.
> >
> > On the other hand, I must admit that ITC's BigDecimal arithmetic is
> > faster while, for example, toString() is slower for the values I've
> > randomly chosen.
> >
> >
> >
> > I agree with you that real performance advantages should be demonstrated
> > by real applications.
> >
> >
> >
> > On the whole, the package is well designed and the code quality is good.
> >
> >
> > The disadvantage I've noticed is unimplemented serialization but this
> > could be easily eliminated.
> >
> >
> >
> > Regards,
> >
> > Elena Semukhina
> >
> > Intel Middleware Products Division
> >
> >
> >
> >> -----Original Message-----
> >
> >> From: Daniel Fridlender [mailto:dfridlender@gmail.com]
> >
> >> Sent: Friday, April 21, 2006 2:52 AM
> >
> >> To: harmony-dev@incubator.apache.org
> >
> >> Subject: ITC's java.math package contribution
> >
> >
> >> Dear all,
> >
> >
> >> on behalf of ITC I have updated our contribution of the package
> >
> >> java.math including some recent optimizations (HARMONY-199).  I think
> >
> >> it  would be interesting to compare our implementation with the one
> >
> >> donated by Intel (HARMONY-39).  In order to do that, it would be nice
> >
> >> to have a collection of applications were the package is used.
> >
> >
> >> So far, we have tried both implementations with a realistic
> >
> >> application (RSA key generation) and our implementation turned out to
> >
> >> have a significantly better performance.
> >
> >
> >> Another point is that we implemented the full 1.5 API functionality,
> >
> >> which in the case of BigDecimal amounts to having about twice as many
> >
> >> methods as in the 1.4.2 API.  This may have little significance now,
> >
> >> but it will definitely be important when Harmony moves to 1.5
> >
> >
> >> Our implementation uses 1.5 syntax since the 1.5 API includes an Enum
> >
> >> (RoundingMode).
> >
> >> It should be easy to obtain a 1.4.2 implementation of the 1.4.2 API
> > from
> >
> >> it.
> >
> >
> >> Some more information about our development can be found at
> >
> >> http://www.fitc.unc.edu.ar/javadev/math/
> >
> >
> >> Daniel Fridlender
> >
> >
> >> ---------------------------------------------------------------------
> >
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> >
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> >
> >
>
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