Python/maths/numerical_analysis/nevilles_method.py
Tianyi Zheng a8b6bda993
Delete arithmetic_analysis/ directory and relocate its contents (#10824)
* Remove eval from arithmetic_analysis/newton_raphson.py

* Relocate contents of arithmetic_analysis/

Delete the arithmetic_analysis/ directory and relocate its files because
the purpose of the directory was always ill-defined. "Arithmetic
analysis" isn't a field of math, and the directory's files contained
algorithms for linear algebra, numerical analysis, and physics.

Relocated the directory's linear algebra algorithms to linear_algebra/,
its numerical analysis algorithms to a new subdirectory called
maths/numerical_analysis/, and its single physics algorithm to physics/.

* updating DIRECTORY.md

---------

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
2023-10-23 09:31:30 +02:00

56 lines
1.8 KiB
Python
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

"""
Python program to show how to interpolate and evaluate a polynomial
using Neville's method.
Nevilles method evaluates a polynomial that passes through a
given set of x and y points for a particular x value (x0) using the
Newton polynomial form.
Reference:
https://rpubs.com/aaronsc32/nevilles-method-polynomial-interpolation
"""
def neville_interpolate(x_points: list, y_points: list, x0: int) -> list:
"""
Interpolate and evaluate a polynomial using Neville's method.
Arguments:
x_points, y_points: Iterables of x and corresponding y points through
which the polynomial passes.
x0: The value of x to evaluate the polynomial for.
Return Value: A list of the approximated value and the Neville iterations
table respectively.
>>> import pprint
>>> neville_interpolate((1,2,3,4,6), (6,7,8,9,11), 5)[0]
10.0
>>> pprint.pprint(neville_interpolate((1,2,3,4,6), (6,7,8,9,11), 99)[1])
[[0, 6, 0, 0, 0],
[0, 7, 0, 0, 0],
[0, 8, 104.0, 0, 0],
[0, 9, 104.0, 104.0, 0],
[0, 11, 104.0, 104.0, 104.0]]
>>> neville_interpolate((1,2,3,4,6), (6,7,8,9,11), 99)[0]
104.0
>>> neville_interpolate((1,2,3,4,6), (6,7,8,9,11), '')
Traceback (most recent call last):
...
TypeError: unsupported operand type(s) for -: 'str' and 'int'
"""
n = len(x_points)
q = [[0] * n for i in range(n)]
for i in range(n):
q[i][1] = y_points[i]
for i in range(2, n):
for j in range(i, n):
q[j][i] = (
(x0 - x_points[j - i + 1]) * q[j][i - 1]
- (x0 - x_points[j]) * q[j - 1][i - 1]
) / (x_points[j] - x_points[j - i + 1])
return [q[n - 1][n - 1], q]
if __name__ == "__main__":
import doctest
doctest.testmod()