[AccessD] Array faster in DLL?

Gustav,

And finally here is managed C++, which runs instantaneously:

#include "stdafx.h"

#using <mscorlib.dll>
#using <Microsoft.VisualBasic.dll>

using namespace System;

static long ArrayTimeLocal(long lngLoopMax, long& lngTotalCnt);
int _tmain()
{
 long lngTotalCnt = 0;
 long lngResult = 0;

 lngResult = ArrayTimeLocal(1000000, lngTotalCnt);
 Console::WriteLine(String::Format(
  S"Final Result = {0:#,##0}, Final Counter = {1:#,##0}",
  __box(lngResult), __box(lngTotalCnt)));
}

static long ArrayTimeLocal(long lngLoopMax, long& lngTotalCnt) {
 const long lngItems = 100;
 long alngTmp[lngItems-1][2];
 long lngLoop;
 long lngItem;
 long lngResult=0;
 double dblStart;
 double dblStop;
 long lngSeconds;

 Console::WriteLine("Array looping test started...");
 dblStart = Microsoft::VisualBasic::DateAndTime::Timer;
 lngTotalCnt = 0;
 for (lngLoop=0; lngLoop < lngLoopMax; lngLoop++) {
  for (lngItem=0; lngItem < lngItems; lngItem++) {
   alngTmp[lngItem][0] = lngLoop * 10;
   if (alngTmp[lngItem][0] / 10 == 100) lngResult = 1;
   else lngResult = 0;
   lngTotalCnt++;
  }
 }
 dblStop = Microsoft::VisualBasic::DateAndTime::Timer;
 Console::WriteLine("Array looping test ended.");
 lngSeconds = (long)(dblStop - dblStart);
 return lngSeconds;
}

Output
---------
Array looping test started...
Array looping test ended.
Final Result = 0, Final Counter = 100,000,000

And it takes ~18 seconds on my PC to run this test ADDITIONALLY looped 100
times....

Shamil

----- Original Message ----- 
From: "Shamil Salakhetdinov" <shamil at users.mns.ru>
To: "Access Developers discussion and problem solving"
<accessd at databaseadvisors.com>
Sent: Monday, October 31, 2005 1:34 PM
Subject: Re: [AccessD] Array faster in DLL?


> Gustav,
>
> I think if you say that you have forgotten 99% Fortran then you can
convert
> your code into C++ with same efforts as on Fortran.  I mean  - if your
> code is just "arrays shuffling" as you say then VB(A)-> C++ conversion is
> almost line by line...
>
> I did recheck - your code runs just in 5 seconds on VB6 with array bounds
> checks and integer overflow checks switched off. These are 100,000,000
> loops.
>
> I did also test your sample code on C# and VB.NET - and it runs in 5-6
> seconds
> with switched off integer overflow checks (it looks that there is no way
to
> switch off array bounds checks for C# and VB.NET) .
>
> Here is VB.NETcode I used for testing:
>
> VB.NET
> -----------
> Module testArrays
>
>     Sub Main()
>         Dim lngResult As Long = 0
>         Dim lngCnt As Long = 0
>         Dim lngTotalCnt As Long = 0
>         lngResult = ArrayTimeLocal(1000000, lngTotalCnt)
>         lngTotalCnt += lngCnt
>         Console.WriteLine(String.Format( _
>          "Final Result = {0:#,##0}, Final Counter = {1:#,##0}", _
>          lngResult, lngTotalCnt))
>     End Sub
>
>     Function ArrayTimeLocal(ByVal lngLoopMax As Long, ByRef lngTotalCnt As
> Long) As Long
>
>         Const lngItems As Long = 100
>
>         Dim alngTmp(lngItems - 1, 1) As Long
>         Dim lngLoop As Long
>         Dim lngItem As Long
>         Dim lngResult As Long
>         Dim lngSeconds As Long
>         Dim dblStart As Double
>         Dim dblStop As Double
>         Dim lngCnt As Long = 0
>         dblStart = Timer
>
>         For lngLoop = 0 To lngLoopMax - 1
>             For lngItem = 0 To lngItems - 1
>                 alngTmp(lngItem, 1) = lngLoop * 10
>                 If alngTmp(lngItem, 1) / 10 = 100 Then
>                     lngResult = 1
>                 Else
>                     lngResult = 0
>                 End If
>                 lngCnt += 1
>             Next
>         Next
>
>         dblStop = Timer
>         lngSeconds = CLng(dblStop - dblStart)
>
>         lngTotalCnt = lngCnt
>         ArrayTimeLocal = lngSeconds
>
>     End Function
>
> End Module
>
> Output
> ----------
> Final Result = 5, Final Counter = 100,000,000
>
> C#
> ===
> using System;
> using Microsoft.VisualBasic;
>
> namespace testArraysCS
> {
>  class TestArrays
>  {
>   [STAThread]
>   unsafe static void Main(string[] args)
>   {
>    long lngTotalCnt = 0;
>    long lngResult = 0;
>
>    lngResult = ArrayTimeLocal(1000000, ref lngTotalCnt);
>    Console.WriteLine(String.Format(
>     "Final Result = {0:#,##0}, Final Counter = {1:#,##0}",
>     lngResult, lngTotalCnt));
>   }
>
>   unsafe static long ArrayTimeLocal(long lngLoopMax, ref long lngTotalCnt)
{
>    const long lngItems = 100;
>    long[,] alngTmp = new long[lngItems,1] ;
>    long lngLoop;
>    long lngItem;
>    long lngResult=0;
>    double dblStart;
>    double dblStop;
>    long lngSeconds;
>
>    Console.WriteLine("Array looping test started...");
>    dblStart = Microsoft.VisualBasic.DateAndTime.Timer;
>    lngTotalCnt = 0;
>    for (lngLoop=0; lngLoop < lngLoopMax; lngLoop++) {
>     for (lngItem=0; lngItem < lngItems; lngItem++) {
>      alngTmp[lngItem,0] = lngLoop * 10;
>      if (alngTmp[lngItem,0] / 10 == 100) lngResult = 1;
>      else lngResult = 0;
>      lngTotalCnt++;
>     }
>    }
>    dblStop = Microsoft.VisualBasic.DateAndTime.Timer;
>    Console.WriteLine("Array looping test ended.");
>    lngSeconds = (long)(dblStop - dblStart);
>    return lngSeconds;
>   }
>
>  }
> }
>
> Output
> ---------
> Array looping test started...
> Array looping test ended.
> Final Result = 6, Final Counter = 100,000,000
>
> Recapitulation:
> ===========
>
> C++ & Fortran (and COBOL?) rule and rock forever! :)
>
> Shamil
>

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