Minimum time reqd. in calculation ??

[A!]

Hi all,
I am writing an application in VB.NET to calculate the first 1000 prime
numbers.
The issue is the performance.....I want the time taken to be minimum !
I can achieve this in around 15 milliseconds now.
Is there any way I can cut down this limit to less than a millisecond ?
Please suggest.
TIA.

[Morten Wennevik]

Hi A!,

There is no way we can tell you how to optimize your code when you don't show us the code :P
There is no way we can compare 15 ms to any of our own code either since you don't tell us what system you are running on.

--
Happy Coding!
Morten Wennevik [C# MVP]

[One Handed Man \( OHM - Terry Burns \)]

Post your code is a good start

--

OHM ( Terry Burns )
. . . One-Handed-Man . . .
If U Need My Email ,Ask Me

Time flies when you don't know what you're doing

"A!" <an*******@discussions.microsoft.com> wrote in message
news:%2****************@TK2MSFTNGP09.phx.gbl...

Hi all,
I am writing an application in VB.NET to calculate the first 1000 prime
numbers.
The issue is the performance.....I want the time taken to be minimum !
I can achieve this in around 15 milliseconds now.
Is there any way I can cut down this limit to less than a millisecond ?
Please suggest.
TIA.

[A!]

Thanks both of you.
Here's my code :
*****************************

Imports System.Math

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button3.Click

Me.SuspendLayout()

Dim i As Int16 = 3

Dim intCounter As Int16 = 2

Dim intDivider As Int16

Dim intRunner As Int16

Dim bolIsPrime As Boolean

Dim arrPrimes(999) As String

arrPrimes(0) = 2

arrPrimes(1) = 3

Dim sw As New StopWatch
Do While Not intCounter > 999

intDivider = Ceiling(Sqrt(i))

If intDivider > 1 Then

For intRunner = 3 To intDivider Step 2

If (i Mod intRunner) = 0 Then

bolIsPrime = False

Exit For

End If

bolIsPrime = True

Next

If bolIsPrime Then

arrPrimes(intCounter) = i

intCounter += 1

End If

End If

i += 2

Loop

'Comment these three lines out when measuring speed of the algo only

ListBox1.BeginUpdate()

ListBox1.Items.AddRange(arrPrimes)

ListBox1.EndUpdate()

Label1.Text = (sw.Peek() / 10).ToString 'Time elapsed.

Me.ResumeLayout()

End Sub


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click

ListBox1.Items.Clear()

End Sub

*****************************

Also, I am running this on a P-4, 512 RAM, 40 GB HDD.

Thanks.


"One Handed Man ( OHM - Terry Burns )" <news.microsoft.com> wrote in message
news:%2***************@TK2MSFTNGP14.phx.gbl...

Post your code is a good start

--

OHM ( Terry Burns )
. . . One-Handed-Man . . .
If U Need My Email ,Ask Me

Time flies when you don't know what you're doing

"A!" <an*******@discussions.microsoft.com> wrote in message
news:%2****************@TK2MSFTNGP09.phx.gbl...

Hi all,
I am writing an application in VB.NET to calculate the first 1000 prime
numbers.
The issue is the performance.....I want the time taken to be minimum !
I can achieve this in around 15 milliseconds now.
Is there any way I can cut down this limit to less than a millisecond ?
Please suggest.
TIA.

[Morten Wennevik]

Well, I tried translating your code to C# and I got 218ms (on a Celeron 1.7Ghz) when filling the ListBox and less than 100ns when not filling (ie too small a value for TimeSpan), so the time is spent on filling the ListBox, which I don't think you can speed up.

I had to make a couple of adjustments to your code, so it may not be correct. I also had to guess the contents of StopWatch, but it shouldn't affect speed.
Any C# people may want to try to optimize it (or spot errors in the translation).

public class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
this.SuspendLayout();
short i = 3;
short intCounter = 2;
short intDivider;
short intRunner;
bool boolIsPrime = false;
object[] arrPrimes = new object[1000];
arrPrimes[0] = 2;
arrPrimes[1] = 3;

StopWatch sw = new StopWatch();

while(intCounter < 1000)
{
intDivider = (short)Math.Ceiling(Math.Sqrt(i));
if(intDivider > 1)
{
for(intRunner = 3; intRunner <= intDivider; intRunner += 2)
{
if((i % intRunner) == 0)
{
boolIsPrime = false;
break;
}

boolIsPrime = true;
}

if(boolIsPrime)
{
arrPrimes[intCounter] = i;
intCounter++;
}
}

i += 2;
}

listBox1.BeginUpdate();
listBox1.Items.AddRange(arrPrimes);
listBox1.EndUpdate();
label1.Text = sw.Peek().ToString();
this.ResumeLayout();
}
}

class StopWatch
{
private DateTime start;
public StopWatch()
{
start = DateTime.Now;
}

public double Peek()
{
TimeSpan s = DateTime.Now - start;
return (double)(s.Ticks) / 10000;
}
}
--
Happy Coding!
Morten Wennevik [C# MVP]

[Niki Estner]

Google for "sieve of erathostenes". I think that should be a lot faster.

Niki

"A!" <an*******@discussions.microsoft.com> wrote in
news:%2****************@TK2MSFTNGP15.phx.gbl...

Thanks both of you.
Here's my code :
*****************************

Imports System.Math

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button3.Click

Me.SuspendLayout()

Dim i As Int16 = 3

Dim intCounter As Int16 = 2

Dim intDivider As Int16

Dim intRunner As Int16

Dim bolIsPrime As Boolean

Dim arrPrimes(999) As String

arrPrimes(0) = 2

arrPrimes(1) = 3

Dim sw As New StopWatch
Do While Not intCounter > 999

intDivider = Ceiling(Sqrt(i))

If intDivider > 1 Then

For intRunner = 3 To intDivider Step 2

If (i Mod intRunner) = 0 Then

bolIsPrime = False

Exit For

End If

bolIsPrime = True

Next

If bolIsPrime Then

arrPrimes(intCounter) = i

intCounter += 1

End If

End If

i += 2

Loop

'Comment these three lines out when measuring speed of the algo only

ListBox1.BeginUpdate()

ListBox1.Items.AddRange(arrPrimes)

ListBox1.EndUpdate()

Label1.Text = (sw.Peek() / 10).ToString 'Time elapsed.

Me.ResumeLayout()

End Sub


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click

ListBox1.Items.Clear()

End Sub

*****************************

Also, I am running this on a P-4, 512 RAM, 40 GB HDD.

Thanks.


"One Handed Man ( OHM - Terry Burns )" <news.microsoft.com> wrote in
message
news:%2***************@TK2MSFTNGP14.phx.gbl...

Post your code is a good start

--

OHM ( Terry Burns )
. . . One-Handed-Man . . .
If U Need My Email ,Ask Me

Time flies when you don't know what you're doing

"A!" <an*******@discussions.microsoft.com> wrote in message
news:%2****************@TK2MSFTNGP09.phx.gbl...

> Hi all,
> I am writing an application in VB.NET to calculate the first 1000 prime
> numbers.
> The issue is the performance.....I want the time taken to be minimum !
> I can achieve this in around 15 milliseconds now.
> Is there any way I can cut down this limit to less than a millisecond ?
> Please suggest.
> TIA.
>
>

[One Handed Man \( OHM - Terry Burns \)]

Whats StopWatch, is this your code ?, if so post it

--

OHM ( Terry Burns )
. . . One-Handed-Man . . .
If U Need My Email ,Ask Me

Time flies when you don't know what you're doing

"A!" <an*******@discussions.microsoft.com> wrote in message
news:%2****************@TK2MSFTNGP15.phx.gbl...

Thanks both of you.
Here's my code :
*****************************

Imports System.Math

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button3.Click

Me.SuspendLayout()

Dim i As Int16 = 3

Dim intCounter As Int16 = 2

Dim intDivider As Int16

Dim intRunner As Int16

Dim bolIsPrime As Boolean

Dim arrPrimes(999) As String

arrPrimes(0) = 2

arrPrimes(1) = 3

Dim sw As New StopWatch
Do While Not intCounter > 999

intDivider = Ceiling(Sqrt(i))

If intDivider > 1 Then

For intRunner = 3 To intDivider Step 2

If (i Mod intRunner) = 0 Then

bolIsPrime = False

Exit For

End If

bolIsPrime = True

Next

If bolIsPrime Then

arrPrimes(intCounter) = i

intCounter += 1

End If

End If

i += 2

Loop

'Comment these three lines out when measuring speed of the algo only

ListBox1.BeginUpdate()

ListBox1.Items.AddRange(arrPrimes)

ListBox1.EndUpdate()

Label1.Text = (sw.Peek() / 10).ToString 'Time elapsed.

Me.ResumeLayout()

End Sub


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click

ListBox1.Items.Clear()

End Sub

*****************************

Also, I am running this on a P-4, 512 RAM, 40 GB HDD.

Thanks.


"One Handed Man ( OHM - Terry Burns )" <news.microsoft.com> wrote in message news:%2***************@TK2MSFTNGP14.phx.gbl...

Post your code is a good start

--

OHM ( Terry Burns )
. . . One-Handed-Man . . .
If U Need My Email ,Ask Me

Time flies when you don't know what you're doing

"A!" <an*******@discussions.microsoft.com> wrote in message
news:%2****************@TK2MSFTNGP09.phx.gbl...

Hi all,
I am writing an application in VB.NET to calculate the first 1000 prime numbers.
The issue is the performance.....I want the time taken to be minimum !
I can achieve this in around 15 milliseconds now.
Is there any way I can cut down this limit to less than a millisecond ? Please suggest.
TIA.