数值积分/ matlab中的w辛普森

I've created a simple simpson_adaptive method that uses my own simpson method. My simpson method is correct, but my adaptive method does not seem to work for

我创建了一个简单的simpson_adaptive方法，它使用我自己的simpson方法。我的simpson方法是正确的，但是我的自适应方法似乎并不适用

integral( sin(2*pi*x)² ) ranging from -1 to 1

The following code represents the adaptive simpson method. The parameters stand for the function, [a,b] being the interval for the integral and e being the precision.

下面的代码表示自适应的simpson方法。参数表示函数，[a,b]为积分区间，e为精度。

function I = simpson_adaptief(f,a,b,e)

    I1 = simpson(f,a,b,2);
    I2 = simpson(f,a,b,4);

    if (abs(I1-I2)<e)
        I = I2;
    else
        I = simpson_adaptief(f,a,(a+b)/2,e) + simpson_adaptief(f,(a+b)/2,b,e);    
    end
end

n here being the amount of parts the function is being split into.

这里的n是函数被分割成的部分的数量。

function I = simpson(f,a,b,n)
    h = (b-a)/(n);
    p=0;
    q=0;
    for k=1:2:(n-1)
        x=a+h*k;
        p=p+f(x);
    end
    for k=2:2:(n-1)
        x=a+h*k;
        q=q+f(x);
    end
    I = h/3*(f(a)+f(b)+4*p+2*q);
end

Do you guys have any suggestions on what the possible cause of the problem could be? Other functions seem to work.

你们对这个问题的可能原因有什么建议吗?其他功能似乎也起作用。

EDIT: I think it has something to do with my if abs(I1-I2)<e. When I change it to abs(I1-I2)>e, it works, as my program then does the recursion step first.

编辑:我认为这与我的if abs(I1-I2) e时，它就会工作，因为我的程序首先做递归步骤。 有关。当我将它改为abs(i1-i2)>

Thanks in advance!

提前谢谢!

1 个解决方案

#1

I'm pretty new to matlab, but is it possible to call for the function you are creating inside that same function file? That is what I see in your simpson_adaptief function

我对matlab很熟悉，但是可以调用在同一个函数文件中创建的函数吗?这就是我在simpson_adaptief函数中看到的