def gradient(x, y, theta):
"""
Computes a gradient vector from three non-empty numpy.ndarray, using
a for-loop. The two arrays must have the compatible dimensions.
Args:
x: has to be an numpy.ndarray, a matrice of dimension m * n.
y: has to be an numpy.ndarray, a vector of dimension m * 1.
theta: has to be an numpy.ndarray, a vector n * 1.
Returns:
The gradient as a numpy.ndarray, a vector of dimensions n * 1.
None if x, y, or theta are empty numpy.ndarray.
None if x, y and theta do not have compatible dimensions.
Raises:
This function should not raise any Exception.
"""
if (not s.elements(x) or not s.elements(y) or not s.elements(theta)):
return (None)
if (len(list(filter(lambda l: len(l) == len(theta), x))) != len(x)):
return (None)
l = []
for xj in range(len(x[0])):
ss = s.sum_(
np.array([(d.dot(theta, i) - j) * i[xj] for i, j in zip(x, y)]),
lambda l: l)
if (ss == None):
return (None)
l.append(ss / len(y))
return (np.array(l))
def vec_mse(y, y_hat):
"""
Computes the mean squared error of two non-empty numpy.ndarray,
without any for loop. The two arrays must have the same dimensions.
Args:
y: has to be an numpy.ndarray, a vector.
y_hat: has to be an numpy.ndarray, a vector.
Returns:
The mean squared error of the two vectors as a float.
None if y or y_hat are empty numpy.ndarray.
None if y and y_hat does not share the same dimensions.
Raises:
This function should not raise any Exception.
"""
if (not s.elements(y) or not s.elements(y_hat) or len(y) != len(y_hat)):
return (None)
dt = d.dot(y_hat - y, y_hat - y)
if (dt != None):
return (dt / len(y))
return (0)
def mat_vec_prod(x, y):
"""
Computes the product of two non-empty numpy.ndarray, using a
for-loop. The two arrays must have compatible dimensions.
Args:
x: has to be an numpy.ndarray, a matrix of dimension m * n.
y: has to be an numpy.ndarray, a vector of dimension n * 1.
Returns:
The product of the matrix and the vector as a vector of dimension m *
1.
None if x or y are empty numpy.ndarray.
None if x and y does not share compatibles dimensions.
Raises:
This function should not raise any Exception.
"""
if (not s.elements(x) or not s.elements(y)):
return (None)
if (len(list(filter(lambda l: len(l) == len(y), x))) == len(x)):
return (np.array(list(map(lambda l: d.dot(l, y), x))))
return (None)
def mat_mat_prod(x, y):
"""
Computes the product of two non-empty numpy.ndarray,
for-loop. The two arrays must have compatible dimensions.
Args:
x: has to be an numpy.ndarray, a matrix of dimension m
y: has to be an numpy.ndarray, a vector of dimension n
Returns:
The product of the matrices as a matrix of dimension m
None if x or y are empty numpy.ndarray.
None if x and y does not share compatibles dimensions.
Raises:
This function should not raise any Exception.
"""
if (not s.elements(x) or not s.elements(y)):
return (None)
r = np.rot90(y[::-1], 3)
res = []
for row in x:
res.append([d.dot(row, i) for i in r])
return (np.array(res))
def linear_mse(x, y, theta):
"""
Computes the mean squared error of three non-empty numpy.ndarray,
using a for-loop. The three arrays must have compatible dimensions.
Args:
y: has to be an numpy.ndarray, a vector of dimension m * 1.
x: has to be an numpy.ndarray, a matrix of dimesion m * n.
theta: has to be an numpy.ndarray, a vector of dimension n * 1.
Returns:
The mean squared error as a float.
None if y, x, or theta are empty numpy.ndarray.
None if y, x or theta does not share compatibles dimensions.
Raises:
This function should not raise any Exception.
"""
if (not s.elements(x) or not s.elements(y) or not s.elements(theta)):
return (None)
if (len(list(filter(lambda l: len(l) == len(theta), x))) != len(x)):
return (None)
ss = s.sum_(np.array([(d.dot(theta, i) - j)**2 for i, j in zip(X, Y)]),
lambda l: l)
if (ss != None):
return (ss / len(Y))
return (0)