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21 changes: 13 additions & 8 deletions numpy_questions.py
Original file line number Diff line number Diff line change
Expand Up @@ -37,12 +37,11 @@ def max_index(X):
If the input is not a numpy array or
if the shape is not 2D.
"""
i = 0
j = 0
if not isinstance(X, np.ndarray) or X.ndim != 2:
raise ValueError("X must be a 2D numpy array.")

# TODO

return i, j
flat_idx = np.argmax(X)
return np.unravel_index(flat_idx, X.shape)


def wallis_product(n_terms):
Expand All @@ -62,6 +61,12 @@ 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

k = np.arange(1, n_terms + 1, dtype=np.float64)
terms = (2 * k / (2 * k - 1)) * (2 * k / (2 * k + 1))
return 2.0 * np.prod(terms)
79 changes: 57 additions & 22 deletions sklearn_questions.py
Original file line number Diff line number Diff line change
Expand Up @@ -22,53 +22,88 @@
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
from sklearn.utils.validation import check_is_fitted
from sklearn.utils.validation import check_X_y
from sklearn.utils.validation import check_array


class OneNearestNeighbor(BaseEstimator, ClassifierMixin):
"OneNearestNeighbor classifier."
class OneNearestNeighbor(ClassifierMixin, BaseEstimator):
"""OneNearestNeighbor classifier."""

def __init__(self): # noqa: D107
pass

def fit(self, X, y):
"""Write docstring.
"""Fit the classifier by memorizing the training set.

Parameters
----------
X : ndarray of shape (n_samples, n_features)
Training input samples.

y : ndarray of shape (n_samples,)
Target class labels.

And describe parameters
Returns
-------
self : OneNearestNeighbor
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_ = X
self.y_ = y
return self

def predict(self, X):
"""Write docstring.
"""Predict class labels for samples in `X`.

Parameters
----------
X : ndarray of shape (n_queries, n_features)
Input samples.

And describe parameters
Returns
-------
y_pred : ndarray of shape (n_queries,)
Predicted class labels.
"""
check_is_fitted(self)
check_is_fitted(
self, attributes=["X_", "y_", "classes_", "n_features_in_"]
)
X = check_array(X)
y_pred = np.full(
shape=len(X), fill_value=self.classes_[0],
dtype=self.classes_.dtype
)
if X.shape[1] != self.n_features_in_:
raise ValueError(
f"X has {X.shape[1]} features, but {self.__class__.__name__} "
f"is expecting {self.n_features_in_} features as input"
)

# XXX fix
return y_pred
diff = X[:, np.newaxis, :] - self.X_[np.newaxis, :, :]
dists = np.sum(diff ** 2, axis=2)
nn_idx = np.argmin(dists, axis=1)
return self.y_[nn_idx]

def score(self, X, y):
"""Write docstring.
"""
Compute accuracy of the classifier on the given test data and labels.

And describe parameters
Parameters
----------
X : ndarray of shape (n_samples, n_features)
Test samples.

y : ndarray of shape (n_samples,)
True labels for `X`.

Returns
-------
accuracy : float
Mean accuracy of predictions on `X` compared to `y`.
"""
X, y = check_X_y(X, y)
y_pred = self.predict(X)

# XXX fix
return y_pred.sum()
return float(np.mean(y_pred == y))
4 changes: 2 additions & 2 deletions students.txt
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ Burtin Léo
Chaabouni Kenza
Chauhan Bhavesh
Chou Wei-Chieh X
Clot Augustin
Clot Augustin X
De Sauvan D'Aramon Ithier X
Descazeaud Lucien X
Despréaux Maxime X
Expand Down Expand Up @@ -60,7 +60,7 @@ Liard Eléanor X
Liu Guangyue X
Liu Yunxian X
Lucille Maximilien X
Mahé Blanche
Mahé Blanche X
Martin Justin X
Massias Mathurin
Massoud Alexandre.....X
Expand Down
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