예제 #1
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def project(v, w):
	"""return the projection of v onto the direction w"""
	projection_length = dot(v, w)
	return scalar_multiply(projection_length, w)
예제 #2
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def directional_variance_i(x_i, w):
	"""the variance of the row x_i in the direction determined by w"""
	return dot(x_i, direction(w)) ** 2
예제 #3
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def directional_variance_gradient_i(x_i, w):
	"""the contribution of row x_i to the gradient of the direction-w variance"""
	projection_length = dot(x_i, direction(w))
	return [ 2 * projection_length * x_ij for x_ij in x_i]
예제 #4
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def transform_vector(v, components):
	return [dot(v, w) for w in components]