# ANDERSON

The ANDERSON node is based on a numpy or scipy function. The description of that function is as follows: Anderson-Darling test for data coming from a particular distribution. The Anderson-Darling test tests the null hypothesis that a sample is drawn from a population that follows a particular distribution. For the Anderson-Darling test, the critical values depend on which distribution is being tested against. This function works for normal, exponential, logistic, or Gumbel (Extreme Value Type I) distributions. Params: select_return : This function has returns multiple objects ['statistic', 'critical_values', 'significance_level']. Select the desired one to return. See the respective function docs for descriptors. x : array_like Array of sample data. dist : {'norm', 'expon', 'logistic', 'gumbel', 'gumbel_l', 'gumbel_r', 'extreme1'} The type of distribution to test against. The default is 'norm'. The names 'extreme1', 'gumbel_l' and 'gumbel' are synonyms for the same distribution. Returns: out : DataContainer type 'ordered pair', 'scalar', or 'matrix'
Python Code
from flojoy import OrderedPair, flojoy, Matrix, Scalar
import numpy as np
from typing import Literal

import scipy.stats

@flojoy
def ANDERSON(
default: OrderedPair | Matrix,
dist: str = "norm",
select_return: Literal[
"statistic", "critical_values", "significance_level"
] = "statistic",
) -> OrderedPair | Matrix | Scalar:
"""The ANDERSON node is based on a numpy or scipy function.

The description of that function is as follows:

Anderson-Darling test for data coming from a particular distribution.

The Anderson-Darling test tests the null hypothesis that a sample is drawn from a population that follows a particular distribution.
For the Anderson-Darling test, the critical values depend on which distribution is being tested against.
This function works for normal, exponential, logistic, or Gumbel (Extreme Value Type I) distributions.

Parameters
----------
select_return : This function has returns multiple objects ['statistic', 'critical_values', 'significance_level'].
Select the desired one to return.
See the respective function docs for descriptors.
x : array_like
Array of sample data.
dist : {'norm', 'expon', 'logistic', 'gumbel', 'gumbel_l', 'gumbel_r', 'extreme1'}, optional
The type of distribution to test against.
The default is 'norm'.
The names 'extreme1', 'gumbel_l' and 'gumbel' are synonyms for the same distribution.

Returns
-------
DataContainer
type 'ordered pair', 'scalar', or 'matrix'
"""

result = scipy.stats.anderson(
x=default.y,
dist=dist,
)

return_list = ["statistic", "critical_values", "significance_level"]
if isinstance(result, tuple):
res_dict = {}
num = min(len(result), len(return_list))
for i in range(num):
res_dict[return_list[i]] = result[i]
result = res_dict[select_return]
else:
result = result._asdict()
result = result[select_return]

if isinstance(result, np.ndarray):
result = OrderedPair(x=default.x, y=result)
else:
assert isinstance(
result, np.number | float | int
), f"Expected np.number, float or int for result, got {type(result)}"
result = Scalar(c=float(result))

return result


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