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Given a set of data vectors in the following format: |
Given a set of data vectors in the following format: |
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Revision as of 18:23, 29 June 2009
Multiple regression
You are encouraged to solve this task according to the task description, using any language you may know.
You are encouraged to solve this task according to the task description, using any language you may know.
Given a set of data vectors in the following format:
Compute the vector using ordinary least squares regression using the following equation:
You can assume y is given to you as an array, and x is given to you as a two-dimensional array.
Ruby
Using the standard library Matrix class:
<lang ruby>require 'matrix'
def regression_coefficients y, x
y = Matrix.column_vector y.map { |i| i.to_f } x = Matrix.columns x.map { |xi| xi.map { |i| i.to_f }}
(x.t * x).inverse * x.t * y
end </lang>
Testing: <lang ruby> regression_coefficients([1, 2, 3, 4, 5], [ [2, 1, 3, 4, 5] ]) # => Matrix0.981818181818182 </lang>