An incremental_search algorithm

最新推荐文章于 2024-10-31 14:44:51 发布

原创最新推荐文章于 2024-10-31 14:44:51 发布 · 273 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#python

本文介绍了一种用于求解函数根的增量搜索算法，通过在指定区间内逐步增加步长进行搜索，直至找到根的近似位置。算法详细描述了如何在函数符号变化处定位根，并提供了迭代次数作为算法效率的衡量标准。

"""An incremental search algorithm"""
import numpy as np
def incremental_search(f,a,b,dx):
    """
    f:the function to sovle
    a:the left boundary x-axis value
    b:the right boundary x-axis value
    dx:the invreamental value in searching
    return:the x-axis value of the root,
    number of interations used
    """
    fa = f(a)
    c = a +dx
    fc = f(c)
    n = 1
    while np.sign(fa) == np.sign(fc):
        if a >= b:
            return a - dx,n
        a = c
        fa = fc
        c = a+dx
        fc = f(c)
        n+=1
    if fa == 0:
        return a,n
    elif fc == 0:
        return c,n
    else:
        return (a+c)/2.,n
"""
For example
"""
y = lambda x:x**3 +2.0*x**2-5
root,interations = incremental_search(y,-5.,5.,0.001)
print("root is",root)
print("interations:",interations)