用Riemann Sum(Python)进行数值积分 [英] Numerical Integration with Riemann Sum (Python)

问题描述

我有以下代码，但运行时会给出0.0 由于我正在尝试在间隔[0, pi]中对sin(x)进行积分，因此它应该返回2的值. 请告知.

I have the following code but when it is run, it gives 0.0 It should return a value of 2 since I am attempting to integrate sin(x) in the interval [0, pi]. Please advise.

from math import sin, pi

def Rsum(a,b):
    for i in range(1001):
        s = 0
        delx = float((b-a)/1000)
        g = i*delx
        h = (i+1)*delx

        y_i = float(sin(a+g))
        y_ii = float(sin(a+h))
        s += 1/2 * (y_i + y_ii) * delx

    return s

print Rsum(0,pi)

推荐答案

1/2在python 2.x中为0.它正在执行整数除法和四舍五入.您可以通过使用0.5或1.0/2来获得所需的内容.

1/2 is 0 in python 2.x. It is performing integer division and rounding down. You can get what you want by using 0.5 or 1.0/2 instead.

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