CODEWITHSUNDEEP
pythonalgorithmmath
L.R.
L.R.

Reputation: 455

Bolzano's algorithm on Python

I am trying to code the bissection method on python, and I am having trouble applying it to different functions. So far I have this code:

def Bolzano(fonction, a, b, tol=0.000001):
   while abs(b-a)>tol:
       m=(a+b)/2
       if cmp(fonction(m))==cmp(fonction(a)):
           a=m
       else:
           b=m
   return a, b

This code doesn't work well because I don't know how to define the function. Writing simply

Bolzano(3*x,0.5,1.0)

does not work because x is not defined. Because of this, I can't check if anything is wrong with the rest of the code.

Of course I could first define the function and then just apply it, but I want to be able to change the functions whils always keeping the same algorithm without rewriting it. Any help?

Upvotes: 0

Views: 1356

Answers (1)

IVlad
IVlad

Reputation: 43497

You could use lambdas:

Bolzano(lambda x: 3*x,0.5,1.0)

Or define a function that you pass to Bolzano:

def f(x):
    return 3*x

Bolzano(f, 0.5, 1.0)

Then you can just keep adding functions:

def f(x):
    return 3*x

def f1(x):
    return 3*x+6

Bolzano(f, 0.5, 1.0)
Bolzano(f1, 0.5, 1.0)

Upvotes: 2

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