[英]Why Simpson's rule of integration rewritten in Python giving a different result?
以下源代碼是辛普森積分規則的實現。
C# 源代碼。
using System;
public class Simpson
{
private double Function(double x)
{
return 1.0 / (1.0 + Math.Pow(x, 5)); //Define the function f(x)
}
public double Compute(double a, double b, int n)
{
double[] x = new double[n + 1];
double delta_x = (b - a) / n;
x[0] = a;
for (int j = 1; j <= n; j++)//calculate the values of x1, x2, ...xn
{
x[j] = a + delta_x * j;
}
double sum = Function(x[0]);
for (int j = 1; j < n; j++)
{
if (j % 2 != 0)
{
sum += 4 * Function(x[j]);
}
else
{
sum += 2 * Function(x[j]);
}
}
sum += Function(x[n]);
double integration = sum * delta_x / 3;
return integration;
}
}
public class MainClass
{
public static void Main()
{
Simpson simpson = new Simpson();
double a = 0d;//lower limit a
double b = 3d;//upper limit b
int n = 6;//Enter step-length n
if (n % 2 == 0)//n must be even
{
Console.WriteLine(simpson.Compute(a, b, n));
}
else
{
Console.WriteLine("n should be an even number");
}
Console.ReadLine();
}
}
Output:
1.07491527775614
.
Python 源代碼。
import math
# function to be integrated
def Function(x):
return 1.0 / (1.0 + math.pow(x, 5)); #Define the function f(x)
def Simpson(a, b, n):
x = [0] * (n + 1);
delta_x = (b - a) / n;
x[0] = a;
for j in range(1,n):#calculate the values of x1, x2, ...xn
x[j] = a + delta_x * j;
sum = Function(x[0]);
for j in range( 1, n):
if (j % 2 != 0):
sum = sum + 4 * Function(x[j]);
else:
sum = sum + 2 * Function(x[j]);
sum += Function(x[n]);
integration = sum * delta_x / 3;
return integration;
# Main Program
a = 0.0; # lower limit a
b = 3.0; # upper limit b
n = 6; # Enter step-length n
if (n % 2 == 0): # n must be even
print(Simpson(a, b, n));
else:
print("n should be an even number");
Output:
1.2408988843135185
C# 程序的 output 不同於 Python 的 output。
這是為什么?
range(1,n)
表示[1, n)
。 而(int j = 1; j <= n; j++)
代表[1, n]
。
可能會有更多不同,但這是最明顯的一個。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.