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23 changes: 19 additions & 4 deletions numpy_questions.py
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,7 @@
This will be enforced with `flake8`. You can check that there is no flake8
errors by calling `flake8` at the root of the repo.
"""

import numpy as np


Expand All @@ -40,8 +41,17 @@ def max_index(X):
i = 0
j = 0

# TODO
# check that X is a numpy array
if not isinstance(X, np.ndarray):
raise ValueError("X must be a numpy array.")

# check it has 2 dimensions
if len(X.shape) != 2:
raise ValueError("X must be 2-dimensional.")

max_value = np.argmax(X) # find the maximum

i, j = np.unravel_index(max_value, X.shape) # find where is the maximum
return i, j


Expand All @@ -62,6 +72,11 @@ def wallis_product(n_terms):
pi : float
The approximation of order `n_terms` of pi using the Wallis product.
"""
# XXX : The n_terms is an int that corresponds to the number of
# terms in the product. For example 10000.
return 0.
if not isinstance(n_terms, int) or n_terms < 0:
raise ValueError("n_terms must be a non-negative integer")

if n_terms == 0:
return 1.0
n = np.arange(1, n_terms + 1) # the range for n (times we multiply)
wallis_product = np.prod((4 * n**2) / (4 * n**2 - 1))
return wallis_product * 2 # we multiply by two to find pi
58 changes: 44 additions & 14 deletions sklearn_questions.py
Original file line number Diff line number Diff line change
Expand Up @@ -19,56 +19,86 @@
for the methods you code and for the class. The docstring will be checked using
`pydocstyle` that you can also call at the root of the repo.
"""

import numpy as np
from sklearn.base import BaseEstimator
from sklearn.base import ClassifierMixin
from sklearn.utils.validation import check_X_y
from sklearn.utils.validation import check_array
from sklearn.utils.validation import check_is_fitted
from sklearn.utils.multiclass import check_classification_targets


class OneNearestNeighbor(BaseEstimator, ClassifierMixin):
"OneNearestNeighbor classifier."
class OneNearestNeighbor(ClassifierMixin, BaseEstimator):
"""One Nearest Neighbor classifier."""

def __init__(self): # noqa: D107
pass

def fit(self, X, y):
"""Write docstring.
"""Fit the OneNearestNeighbor class.

Parameters
----------
X : array, shape(n_samples, n_features) - training data
Y : array, shape(n_samples, n_features) - target

And describe parameters
Return
----------
self : OneNearestNeighbor - the fitted estimator
"""
X, y = check_X_y(X, y)
check_classification_targets(y)
self.classes_ = np.unique(y)
self.n_features_in_ = X.shape[1]

# XXX fix
self.X_train_ = X
self.y_train_ = y

return self

def predict(self, X):
"""Write docstring.
"""Prediction of the OneNearestNeighbor class.

Parameters
----------
X : array, shape(n_samples, n_features) - test data


And describe parameters
Return
----------
y_pred : array, shape(n_samples,) -
the predicted class for each sample
"""
check_is_fitted(self)
X = check_array(X)
X = self._validate_data(X, reset=False)

y_pred = np.full(
shape=len(X), fill_value=self.classes_[0],
dtype=self.classes_.dtype
)

# XXX fix
for i, x in enumerate(X):
distances = np.sqrt(np.sum((self.X_train_ - x) ** 2, axis=1))
nearest_index = np.argmin(distances)
y_pred[i] = self.y_train_[nearest_index]

return y_pred

def score(self, X, y):
"""Write docstring.
"""Give accuracy score.

Parameters
----------
X : array, shape(n_samples, n_features) - test data
y : array, shape(n_samples, n_features) - train data

Return
----------
accuracy : float - the mean accuracy for the prediction

And describe parameters
"""
X, y = check_X_y(X, y)
y_pred = self.predict(X)

# XXX fix
return y_pred.sum()
accuracy = np.mean(y_pred == y)
return accuracy