diff --git a/maths/series/geometric_mean.py b/maths/series/geometric_mean.py new file mode 100644 index 000000000..50ae54ad6 --- /dev/null +++ b/maths/series/geometric_mean.py @@ -0,0 +1,75 @@ +""" +GEOMETRIC MEAN : https://en.wikipedia.org/wiki/Geometric_mean +""" + + +def is_geometric_series(series: list) -> bool: + """ + checking whether the input series is geometric series or not + + >>> is_geometric_series([2, 4, 8]) + True + >>> is_geometric_series([3, 6, 12, 24]) + True + >>> is_geometric_series([1, 2, 3]) + False + >>> is_geometric_series([0, 0, 3]) + False + + """ + if len(series) == 1: + return True + try: + common_ratio = series[1] / series[0] + for index in range(len(series) - 1): + if series[index + 1] / series[index] != common_ratio: + return False + except ZeroDivisionError: + return False + return True + + +def geometric_mean(series: list) -> float: + """ + return the geometric mean of series + + >>> geometric_mean([2, 4, 8]) + 3.9999999999999996 + >>> geometric_mean([3, 6, 12, 24]) + 8.48528137423857 + >>> geometric_mean([4, 8, 16]) + 7.999999999999999 + >>> geometric_mean(4) + Traceback (most recent call last): + ... + ValueError: Input series is not valid, valid series - [2, 4, 8] + >>> geometric_mean([1, 2, 3]) + Traceback (most recent call last): + ... + ValueError: Input list is not a geometric series + >>> geometric_mean([0, 2, 3]) + Traceback (most recent call last): + ... + ValueError: Input list is not a geometric series + >>> geometric_mean([]) + Traceback (most recent call last): + ... + ValueError: Input list must be a non empty list + + """ + if not isinstance(series, list): + raise ValueError("Input series is not valid, valid series - [2, 4, 8]") + if len(series) == 0: + raise ValueError("Input list must be a non empty list") + if not is_geometric_series(series): + raise ValueError("Input list is not a geometric series") + answer = 1 + for value in series: + answer *= value + return pow(answer, 1 / len(series)) + + +if __name__ == "__main__": + import doctest + + doctest.testmod()