Solved

Math calc VB.NET in XP or WIN98

Posted on 2004-03-23
6
310 Views
Last Modified: 2012-08-14
I am developing a differential element solution in Visual Basic .NET

For this I need to perform matrix calculations for matrixes between 100 and 10000 elements. I defined all variables and arrays as double. Number of double calculations are between 10^5 and 10^10.

All calculations seems to converge correctly when done on a XP-proffesional platform (Pentium 4), where my IDE Visual basic is installed.

After installation on Win98 (Pentium III), the program seems to work fine. However, occasionally the calculations crash due to a NaN error. Notice that exactly the same calculations do not crash at the XP platform.

During the calculations the following functions are used from System.math: Sqrt() and Log().
Further I use a double division of two small doubles, which result should be between 0 and 2.
The former two small doubles are formed by addition of 100 to 10000 double*double calculations.

I tried using different .NET Frameworks, but that did not help.

Please help....
0
Comment
Question by:vohaan
  • 3
  • 3
6 Comments
 
LVL 69

Expert Comment

by:Éric Moreau
Comment Utility
I had some similar problems in VB6 with rounding operations (see http://www.experts-exchange.com/Programming/Programming_Languages/Visual_Basic/Q_20311047.html ).

I am sure that something changed in XP but I don't what and why.

In my case, I ended up building my own rounding function.
0
 

Author Comment

by:vohaan
Comment Utility
I do not use any rounding functions, but may be the rouding of the values after the double calculations has some effect. The problem is I only find differences after many double calculations, the first calculations are not notticable different.

Except for different OS I tied also different Processos (P4 and P3) the problem is the same: Win98 gives a wrong result....
0
 
LVL 69

Expert Comment

by:Éric Moreau
Comment Utility
I didn't want to mean that only the Round function has problems. I meant that something had changed into the Windows Math library.
0
How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

 

Author Comment

by:vohaan
Comment Utility
It could be possible. Do you know of how to correct it?

I know that VB.NET uses the .NET Framework to implement some math functions. But simple multiplication of doubles is that part of VB.NET source or distributed with .NET Framework? Or are there any other files for this?

Are double calculations not transferred to the processor and evaluated in 'hardware' ? Maybe Win98 interpretes the results coming back form the processor differently ?

0
 
LVL 69

Accepted Solution

by:
Éric Moreau earned 250 total points
Comment Utility
>>It could be possible. Do you know of how to correct it?

No that's why I created my own rounding function.
0
 

Author Comment

by:vohaan
Comment Utility
I found out that sometimes the calculations are going correct at WIN98 and sometimes they are going false. Nothing changes only the same calulation again and again.

Is this kind of instability known for Win98?
0

Featured Post

Threat Intelligence Starter Resources

Integrating threat intelligence can be challenging, and not all companies are ready. These resources can help you build awareness and prepare for defense.

Join & Write a Comment

Suggested Solutions

The debugging module of the VB 6 IDE can be accessed by way of the Debug menu item. That menu item can normally be found in the IDE's main menu line as shown in this picture.   There is also a companion Debug Toolbar that looks like the followin…
Enums (shorthand for ‘enumerations’) are not often used by programmers but they can be quite valuable when they are.  What are they? An Enum is just a type of variable like a string or an Integer, but in this case one that you create that contains…
Get people started with the utilization of class modules. Class modules can be a powerful tool in Microsoft Access. They allow you to create self-contained objects that encapsulate functionality. They can easily hide the complexity of a process from…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…

728 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

9 Experts available now in Live!

Get 1:1 Help Now