?
Solved

Integration in C

Posted on 2004-10-12
4
Medium Priority
?
462 Views
Last Modified: 2011-09-20
Hello,
  I want to integrate a function. can anybody suggest me how to improve the code..

for( x = x1; x <= x2; x += 0.01)                  
{      
            f1 = some function(x)
            res += f1/10000.0;
                              
}

IS this right??
Can u plzz show me the code to do integration using any std rules..
TIA
Suma
0
Comment
Question by:hssuma
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
4 Comments
 
LVL 1

Expert Comment

by:RajeshTN
ID: 12295622
hi Suma,

What exactly do you mean by "integrate a function" ? pls explain

Bye
-Rajesh
0
 
LVL 5

Accepted Solution

by:
van_dy earned 60 total points
ID: 12295964
Hi Suma,
       You can use the any of the availiable numerical integration
techniques to calculate the definite integral of a function. Have a look at

http://mathworld.wolfram.com/NumericalIntegration.html

the techniques range from fairly complex Newton-cote's method
to relatively simple trapezoidal rule.  You  need to be more specific
about the algorithm you want to implement.
As a simple implementation, consider dividing your integration space into
N equal sized intervals, and assume that the intervals are small enough
so that the function value in the i-th interval can be approximated as f((X[i] + fX[i+1])/2) throughout;
then a rough integration function can be;

#define N  SOME_LARGE_NUMBER

double function(X)
              double X;
{
        // The body of the function you are integrating over [X1, X2];
}

double integrator(X1,  X2)
               double X1, X2
{
         double Increment = (X2 - X1)/ N;
         double  X = X;
          double Result = 0.0;

          for (; X < X2; X += Increment)
                   Result +=  function(X + Increment/2);

            return Result;
}

Similarily you can implement any of the techniques once you have read about them.
0
 
LVL 5

Expert Comment

by:van_dy
ID: 12295978
Well well, in the integrator(X1, X2), second line reads:

            double X = X1;
             double Result =  0.0;
              .....
              ............
0
 
LVL 5

Expert Comment

by:van_dy
ID: 12295995
and the last line would be

         return Result * Increment;

:D, tooo much hurry;
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Preface I don't like visual development tools that are supposed to write a program for me. Even if it is Xcode and I can use Interface Builder. Yes, it is a perfect tool and has helped me a lot, mainly, in the beginning, when my programs were small…
This tutorial is posted by Aaron Wojnowski, administrator at SDKExpert.net.  To view more iPhone tutorials, visit www.sdkexpert.net. This is a very simple tutorial on finding the user's current location easily. In this tutorial, you will learn ho…
The goal of this video is to provide viewers with basic examples to understand and use structures in the C programming language.
The goal of this video is to provide viewers with basic examples to understand opening and reading files in the C programming language.
Suggested Courses

770 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