Python/arithmetic_analysis/newton_raphson.py
Rohit Joshi f4779bc04a Bug Fixed in newton_raphson_method.py (#1634)
* Bug Fixed

* Fixed newton_raphson_method.py

* Fixed newton_raphson_method.py 2

* Fixed newton_raphson_method.py 3

* Fixed newton_raphson_method.py 4

* Fixed newton_raphson_method.py 5

* Fixed newton_raphson_method.py 6

* Update newton_raphson_method.py

* Update newton_raphson_method.py

* # noqa: F401, F403

* newton_raphson

* newton_raphson

* precision: int=10 ** -10

* return float(x)

* 3.1415926536808043

* Update newton_raphson_method.py

* 2.23606797749979

* Update newton_raphson_method.py

* Rename newton_raphson_method.py to newton_raphson.py
2019-12-15 08:27:07 +01:00

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Python

# Implementing Newton Raphson method in Python
# Author: Syed Haseeb Shah (github.com/QuantumNovice)
# The Newton-Raphson method (also known as Newton's method) is a way to
# quickly find a good approximation for the root of a real-valued function
from decimal import Decimal
from math import * # noqa: F401, F403
from sympy import diff
def newton_raphson(func: str, a: int, precision: int=10 ** -10) -> float:
""" Finds root from the point 'a' onwards by Newton-Raphson method
>>> newton_raphson("sin(x)", 2)
3.1415926536808043
>>> newton_raphson("x**2 - 5*x +2", 0.4)
0.4384471871911695
>>> newton_raphson("x**2 - 5", 0.1)
2.23606797749979
>>> newton_raphson("log(x)- 1", 2)
2.718281828458938
"""
x = a
while True:
x = Decimal(x) - (Decimal(eval(func)) / Decimal(eval(str(diff(func)))))
# This number dictates the accuracy of the answer
if abs(eval(func)) < precision:
return float(x)
# Let's Execute
if __name__ == "__main__":
# Find root of trigonometric function
# Find value of pi
print(f"The root of sin(x) = 0 is {newton_raphson('sin(x)', 2)}")
# Find root of polynomial
print(f"The root of x**2 - 5*x + 2 = 0 is {newton_raphson('x**2 - 5*x + 2', 0.4)}")
# Find Square Root of 5
print(f"The root of log(x) - 1 = 0 is {newton_raphson('log(x) - 1', 2)}")
# Exponential Roots
print(f"The root of exp(x) - 1 = 0 is {newton_raphson('exp(x) - 1', 0)}")