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* [ADDED] Implementation of Geometric Mean. * [pre-commit.ci] auto fixes from pre-commit.com hooks for more information, see https://pre-commit.ci * Rectified type hints * Typo * Apply suggestions from code review --------- Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com> Co-authored-by: Tianyi Zheng <tianyizheng02@gmail.com>
56 lines
1.8 KiB
Python
56 lines
1.8 KiB
Python
"""
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The Geometric Mean of n numbers is defined as the n-th root of the product
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of those numbers. It is used to measure the central tendency of the numbers.
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https://en.wikipedia.org/wiki/Geometric_mean
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"""
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def compute_geometric_mean(*args: int) -> float:
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"""
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Return the geometric mean of the argument numbers.
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>>> compute_geometric_mean(2,8)
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4.0
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>>> compute_geometric_mean('a', 4)
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Traceback (most recent call last):
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...
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TypeError: Not a Number
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>>> compute_geometric_mean(5, 125)
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25.0
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>>> compute_geometric_mean(1, 0)
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0.0
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>>> compute_geometric_mean(1, 5, 25, 5)
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5.0
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>>> compute_geometric_mean(2, -2)
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Traceback (most recent call last):
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...
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ArithmeticError: Cannot Compute Geometric Mean for these numbers.
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>>> compute_geometric_mean(-5, 25, 1)
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-5.0
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"""
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product = 1
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for number in args:
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if not isinstance(number, int) and not isinstance(number, float):
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raise TypeError("Not a Number")
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product *= number
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# Cannot calculate the even root for negative product.
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# Frequently they are restricted to being positive.
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if product < 0 and len(args) % 2 == 0:
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raise ArithmeticError("Cannot Compute Geometric Mean for these numbers.")
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mean = abs(product) ** (1 / len(args))
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# Since python calculates complex roots for negative products with odd roots.
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if product < 0:
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mean = -mean
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# Since it does floating point arithmetic, it gives 64**(1/3) as 3.99999996
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possible_mean = float(round(mean))
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# To check if the rounded number is actually the mean.
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if possible_mean ** len(args) == product:
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mean = possible_mean
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return mean
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if __name__ == "__main__":
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from doctest import testmod
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testmod(name="compute_geometric_mean")
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print(compute_geometric_mean(-3, -27))
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