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Re: Comparing Arbitrary-Precision Integers

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On 2012-07-26, BartC <bc@freeuk.com> wrote:
> [about comparisons]
> However I might just subtract one number from the other; the sign of the
> result will tell you if the relation is < or >=. But you need to check for
> all words zero to distinguish > and =.

This is less efficient than direct comparison.
Direct comparison can stop at the most significant
limb that differs. Subtraction has to process all
limbs of both numbers.

Here's an example in decimal notation:

A : 178359374328607427026709270970624
B : 413327689277727826782971200987096

Just by looking at the first digit one can see that A < B,
whereas performing the subtraction

A-B : -234968314949120399756261930016472

requires processing every digit of A and B.

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Comparing Arbitrary-Precision Integers David T. Ashley <dashley@gmail.com> - 2012-07-26 16:06 -0400
  Re: Comparing Arbitrary-Precision Integers Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-07-26 17:01 -0400
    Re: Comparing Arbitrary-Precision Integers Tim Rentsch <txr@alumni.caltech.edu> - 2012-09-07 11:49 -0700
  Re: Comparing Arbitrary-Precision Integers "BartC" <bc@freeuk.com> - 2012-07-26 22:20 +0100
    Re: Comparing Arbitrary-Precision Integers Ike Naar <ike@sverige.freeshell.org> - 2012-07-26 21:46 +0000
      Re: Comparing Arbitrary-Precision Integers "BartC" <bc@freeuk.com> - 2012-07-26 23:14 +0100
        Re: Comparing Arbitrary-Precision Integers David T. Ashley <dashley@gmail.com> - 2012-07-27 17:55 -0400
  Re: Comparing Arbitrary-Precision Integers Michael Angelo Ravera <maravera@prodigy.net> - 2012-07-26 17:51 -0700
  Re: Comparing Arbitrary-Precision Integers bartek szurgot <basz@no.spam> - 2012-07-27 08:53 +0200
    Re: Comparing Arbitrary-Precision Integers David T. Ashley <dashley@gmail.com> - 2012-07-27 18:02 -0400
      Re: Comparing Arbitrary-Precision Integers Ike Naar <ike@iceland.freeshell.org> - 2012-07-27 22:23 +0000
        Re: Comparing Arbitrary-Precision Integers Keith Thompson <kst-u@mib.org> - 2012-07-27 16:53 -0700
          Re: Comparing Arbitrary-Precision Integers David T. Ashley <dashley@gmail.com> - 2012-07-27 21:25 -0400
      Re: Comparing Arbitrary-Precision Integers Noob <root@127.0.0.1> - 2012-07-30 14:29 +0200
        Re: Comparing Arbitrary-Precision Integers David T. Ashley <dashley@gmail.com> - 2012-07-30 09:28 -0400
  Re: Comparing Arbitrary-Precision Integers "io_x" <a@b.c.invalid> - 2012-07-27 20:46 +0200

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