Numerical Integration 1

[trashcanman]

I am trying to figure out how to do numerical integration, using Simpson's Rule. I could easily do it with Basic, but dang Vista won't run GW Basic. I could also do it with about 1000 rows and then sum it up, but want to avoid that.

It is simply evaluate f(x)*constant, store it, recalculate f(x+dx)*constant, add that to 1st value, recalculate (f(x+dx+dx)*constant, add that, on and on till it reaches the upper limit.

Is there a way to do it using the automatic iteration feature (under Tools)? It would be a sort of FOR TO type statement. Goal Seek won't work, as I am just trying to sum up a lot of calculations, not find a root.

 

[Latexman]

It's easy to do with VBA in Excel.

Good luck,
Latexman

 

[GregLocock]

I'd just do it on the worksheet itself, as in

http://oregonstate.edu/instruct/ch490/lessons/lesson11_files/CURVAREA.XLS

but if you are keen on Basic then VBA is worth learning.

http://www.mathhelpforum.com/math-help/computer-software/31305-excel-vba-simpsons-rule.html

or

http://www.mrexcel.com/forum/archive/index.php/t-99062.html

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[trashcanman]

Thanks, that is some good info. Now, I have to learn VBA (sigh)

 

[IDS]

I have posted on my blog a UDF that will evaluate a definite integral over a specified range for any suitable function, using either Simpson's Rule or the Trapezoidal Rule.

It may be downloded from:

http://newtonexcelbach.wordpress.com/2008/07/05/evaluate-function-update/

Doug Jenkins
Interactive Design Services

http://www.interactiveds.com.au

 

[israelkk]

Try the open source DOSBox emulator for windows it will allow you to run DOS applications that doesn't work in native Windows. I am not sure if it works with Vista but I use it to run DOS applications with graphics that does run under XP.

http://mesh.dl.sourceforge.net/sourceforge/dosbox/DOSBox0.72-win32-installer.exe

 

[electricpete]

What does DOSBox have to do with this thread?

The integration as was mentioned can easily be performed in excel or vba.

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[israelkk]

electricpete

trashcanman complained that GWbasic doesn't run under Vista therefore looked for a spreadsheet alternative. Under DOSbox GWbasic probably may run in Vista.

 

[IRstuff]

You can get Visual Studio Express for C++ or Visual Basic for free from Microsoft. The core of your GWBasic algorithm can probably be ported to VB Express with relatively minor mods.

TTFN

FAQ731-376

 

[electricpete]

israelkk - thanks. I understand now.

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[Feric]

Hi there:

QuickBASIC runs under Vista -- QuickBASIC should take GWBASIC with no problem (just cut and paste)...

Thanks,

Gordan

http://engware.i-dentity.com

 

[trashcanman]

Hey Feric, you are correct, QB4.5 runs okay in Vista. Thanks. Now I can rock and roll.