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Groups > comp.lang.c > #147396

Re: Challenge for Feeb: dealing with large numbers in C

From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c
Subject Re: Challenge for Feeb: dealing with large numbers in C
Date 2019-10-31 03:34 +0000
Organization A noiseless patient Spider
Message-ID <87lft1mvv1.fsf@bsb.me.uk> (permalink)
References (16 earlier) <6bca01ee-02e3-424f-9b43-09d50cea0a93@googlegroups.com> <87y2x3nqhd.fsf@bsb.me.uk> <a07666a8-1e1e-4920-9f0f-d8538b9c9437@googlegroups.com> <87h83qnsqk.fsf@bsb.me.uk> <54740e2a-2881-482c-ad58-620dcfb80111@googlegroups.com>

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already5chosen@yahoo.com writes:
<cut>
> Just to be sure that we are talking about the same thing.
> That's the code for what you call "native comparison":
>
> void bubblesort_Ben(int x[], int nElem)
> {
>   while (nElem > 1) {
>     int swapped = 0;
>     for (int i = 1; i < nElem; ++i) {
>       if (x[i-1] > x[i]) {
>         int temp = x[i-1];
>         x[i-1] = x[i];
>         x[i] = temp;
>         swapped = 1;
>       }
>     }
>     if (!swapped)
>       break;
>     --nElem;
>   }
> }

The code has instrumentation to count swaps, accesses and compares so is
looks like this:

 void bsort2(int n, T A[])
 {
      bool swapped;
      do {
           swapped = false;
           for (int i = 1; i < n; i++)
                if (out_of_order(get(A, i-1), get(A, i))) {
                     swap(A, i-1, i);
                     swapped = true;
                }
           n -= 1;
      } while (swapped);
 }

out_of_order, get and swap are inline functions.

> void bubblesort_Don(int x[], int nElem)
> {
>   while (nElem > 1) {
>     int next_nElem = 0;
>     for (int i = 1; i < nElem; ++i) {
>       if (x[i-1] > x[i]) {
>         int temp = x[i-1];
>         x[i-1] = x[i];
>         x[i] = temp;
>         next_nElem = i;
>       }
>     }
>     nElem = next_nElem;
>   }
> }

That is slightly neater than my version.  I'd added another variable to
avoid using n, and I was not stopping at 1:

 void bsortk(int n, T A[])
 {
      int max_swap = n;
      do {
           int bound = max_swap;
           max_swap = 0;
           for (int i = 1; i < bound; i++)
                if (out_of_order(get(A, i-1), get(A, i))) {
                     swap(A, i-1, i);
                     max_swap = i;
                }
      } while (max_swap);
 }

If I plug-in your exact code (so there's no counting of swaps and so on)
then Kunth's version is always faster (except for one run out of about
15 which was probably down to noise in the measuring).

<cut>
-- 
Ben.

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Thread

Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-20 18:12 -0400
  Re: Challenge for Feeb: dealing with large numbers in C Barry Schwarz <schwarzb@delq.com> - 2019-10-20 18:33 -0700
    Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-20 23:16 -0400
      Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-21 13:15 +0100
        Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 14:40 -0400
          Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-22 00:54 +0100
            Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-22 10:05 +0200
            Re: Challenge for Feeb: dealing with large numbers in C Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-10-23 07:18 -0700
          Re: Challenge for Feeb: dealing with large numbers in C Manfred <noname@invalid.add> - 2019-10-26 20:01 +0200
            Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-26 17:50 -0400
              Re: Challenge for Feeb: dealing with large numbers in C Manfred <noname@add.invalid> - 2019-10-28 16:33 +0100
      Re: Challenge for Feeb: dealing with large numbers in C Barry Schwarz <schwarzb@delq.com> - 2019-10-21 07:56 -0700
      Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 16:46 +0100
        Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 14:57 -0400
          Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 20:53 +0100
            Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 16:05 -0400
              Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 21:12 +0100
            Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 20:08 -0400
              Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-22 10:27 +0200
          Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-22 19:45 +0100
            Re: Challenge for Feeb: dealing with large numbers in C Eli the Bearded <*@eli.users.panix.com> - 2019-10-22 19:58 +0000
            Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-23 11:46 -0400
              Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-23 20:02 +0100
              Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 01:38 +0100
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-23 22:10 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Ike Naar <ike@sdf.lonestar.org> - 2019-10-24 07:24 +0000
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 09:29 -0400
                Re: Challenge for Feeb: dealing with large numbers in C James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-10-24 08:45 -0700
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 11:56 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-24 09:13 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 18:28 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 10:36 +0100
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 09:26 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 18:29 +0100
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 14:38 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 21:30 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-24 11:30 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 20:36 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-24 21:34 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-24 22:42 +0100
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-24 18:59 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-25 02:48 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-26 04:33 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 17:21 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-26 18:47 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 23:24 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-27 00:29 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-27 01:58 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-27 12:02 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 02:08 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-10-26 14:29 -0600
                Re: Challenge for Feeb: dealing with large numbers in C Keith Thompson <kst-u@mib.org> - 2019-10-26 13:36 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-26 22:06 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-26 23:04 +0100
                Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-27 12:49 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-27 18:20 +0000
                Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-27 22:45 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 00:08 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-27 14:57 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 01:08 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 01:44 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 02:31 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 10:42 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 12:45 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 17:39 +0000
                Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-28 20:31 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 20:22 +0000
                Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-28 22:07 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 22:22 +0000
                Re: Challenge for Feeb: dealing with large numbers in C David Brown <david.brown@hesbynett.no> - 2019-10-29 10:17 +0100
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 11:21 +0000
                Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-28 11:05 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 19:26 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 21:08 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-28 21:57 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-28 23:59 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 00:53 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 01:09 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 01:32 +0000
                Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-28 22:44 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-29 03:05 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 11:12 +0000
                Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-29 04:19 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 11:47 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-29 05:03 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 13:16 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 17:13 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 17:35 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ike Naar <ike@sdf.lonestar.org> - 2019-10-30 07:19 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 16:19 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 16:50 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-29 10:03 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-29 17:13 +0000
                Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-29 10:23 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-29 22:20 +0000
                Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-30 03:04 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-30 15:39 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-10-30 09:02 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-30 19:35 +0000
                Re: Challenge for Feeb: dealing with large numbers in C already5chosen@yahoo.com - 2019-10-30 14:11 -0700
                Re: Challenge for Feeb: dealing with large numbers in C Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-10-31 03:34 +0000
                Re: Challenge for Feeb: dealing with large numbers in C Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-11-04 17:02 -0800
                Re: Challenge for Feeb: dealing with large numbers in C Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2019-10-26 12:30 -0400
                Re: Challenge for Feeb: dealing with large numbers in C Robert Wessel <robertwessel2@yahoo.com> - 2019-10-26 12:03 -0500
                Re: Challenge for Feeb: dealing with large numbers in C Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-10-26 14:25 -0600
                Re: Challenge for Feeb: dealing with large numbers in C Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-10-24 18:06 -0700
        Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 22:44 +0100
          Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-21 19:00 -0400
  Re: Challenge for Feeb: dealing with large numbers in C Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-21 10:20 +0800
    Re: Challenge for Feeb: dealing with large numbers in C Bart <bc@freeuk.com> - 2019-10-21 12:44 +0100
  Re: Challenge for Feeb: dealing with large numbers in C Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-21 10:24 +0800
    Re: Challenge for Feeb: dealing with large numbers in C DFS <nospam@dfs.com> - 2019-10-20 23:05 -0400
      Re: Challenge for Feeb: dealing with large numbers in C Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-21 11:32 +0800
  Re: Challenge for Feeb: dealing with large numbers in C Autist <autist69@gmail.com> - 2019-10-29 15:15 +0100

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