发布于 2015-05-12 03:56:52 | 160 次阅读 | 评论: 0 | 来源: 网友投递
Python编程语言
Python 是一种面向对象、解释型计算机程序设计语言,由Guido van Rossum于1989年底发明,第一个公开发行版发行于1991年。Python语法简洁而清晰,具有丰富和强大的类库。它常被昵称为胶水语言,它能够把用其他语言制作的各种模块(尤其是C/C++)很轻松地联结在一起。
这篇文章主要介绍了Python查找函数f(x)=0根的解决方法,涉及Python数学运算函数求解的相关技巧,需要的朋友可以参考下
本文实例讲述了Python查找函数f(x)=0根的解决方法。分享给大家供大家参考。具体实现方法如下:
''' root = ridder(f,a,b,tol=1.0e-9).
Finds a root of f(x) = 0 with Ridder's method.
The root must be bracketed in (a,b).
'''
import error
from math import sqrt
def ridder(f,a,b,tol=1.0e-9):
fa = f(a)
if fa == 0.0: return a
fb = f(b)
if fb == 0.0: return b
if fa*fb > 0.0: error.err('Root is not bracketed')
for i in range(30):
# Compute the improved root x from Ridder's formula
c = 0.5*(a + b); fc = f(c)
s = sqrt(fc**2 - fa*fb)
if s == 0.0: return None
dx = (c - a)*fc/s
if (fa - fb) < 0.0: dx = -dx
x = c + dx; fx = f(x)
# Test for convergence
if i > 0:
if abs(x - xOld) < tol*max(abs(x),1.0): return x
xOld = x
# Re-bracket the root as tightly as possible
if fc*fx > 0.0:
if fa*fx < 0.0: b = x; fb = fx
else: a = x; fa = fx
else:
a = c; b = x; fa = fc; fb = fx
return None
print 'Too many iterations'