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Date: Wed, 13 Jun 2012 21:25:47 -0400
From: pete <pfiland@mindspring.com>
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Subject: Open letter to Ian Collins
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Ian Collins wrote:
> 
> On 05/27/12 07:30 PM, jacob navia wrote:
> > Le 27/05/12 05:16, Ian Collins a écrit :
> >> On 05/27/12 10:22 AM, jacob navia wrote:
> >>> Hi Ian
> >>>
> >>> In the c++ newsgroup you asked me
> >>> for an example of the ccl performance
> >>> It was something with building a huge list, then sorting it, if I
> >>> remember correctly...
> >>>
> >>> I have built this example code:
> >>>
> >> <snip>
> >>
> >> I get a segv when I run the example.
> >> Running in dbx with access checking
> >> enabled shows:
> >
> > I corrected that yesterday.
> > When you asked me gthis example I was in the
> > middle of a reorganization of heap.c. Look at the latest update
> 
> OK,
> I thought I had but I didn't notice wget saving the file as cc.zip.1
> rather than overwriting the version I downloaded earlier in the week.
> 
> Anyway I ran ran the code
> built with Sun Studio rather than gcc because
> it runs quite a bit faster.  As I expected, the big difference was in
> sorting:
> 
> ccl version:
> 
> To sort     85.6384S
> 
> C++ version (std::list.sort()):
> 
> To sort     18.7927S
> 
> Iteration was closer:
> 
> To access    2.80655S (ccl)
> To access    1.82896S

/*
** Would you please run this program
** and let me know what the output is?
** I'm of the opinion that the QSORT function
** which is currently in listgen.c, at
** http://code.google.com/p/ccl/downloads/detail?name=ccl.zip&can=2&q= 
** has approximately zero chance of correctly sorting
** a data set of as many as 10000000 psuedorandom keys.
*/
#include <stdlib.h>

#include "containers.h"
#include "intlist.h"

#define N 10000000

int 
main(void)
{
    intList *L1;
    size_t i;
    int d;
    long unsigned sum=0,newSum=0;
    Iterator *it;
    int *pint, last_pint;
    
    L1 = iintList.Create(sizeof(int));
    iintList.UseHeap(L1,NULL); // Use specialized Heap
    // Add N random numbers to the integer list
    for (i=0; i<N;i++) {
        d = rand();
        sum += d;
        iintList.Add(L1,d);
    }
    // Sort it
    iintList.Sort(L1);
    // Go through the sorted list using an iterator
    it = iintList.NewIterator(L1);
    i=0;
    pint = it->GetFirst(it);
    while (pint != NULL) {
        last_pint = *pint;
        newSum += last_pint;
        pint = it->GetNext(it);
        if (pint != NULL && last_pint > *pint) {
            puts("\n\nThe data is not sorted.\n\n");
            iintList.Finalize(L1);
            exit(EXIT_SUCCESS);
        }
    }
    // Verify that both sums are identical
    if (sum != newSum) {
        printf("Failed\n");
    } else {
        printf("Sum = %lu\n",sum);
    }
    // Destroy the list
    iintList.Finalize(L1);
    return 0;
}

-- 
pete