Exponential Regression Newton’s Method – Advanced

Exponential Regression Newton’s Method – Advanced

Property 1: Given samples {x1, …, xn} and {y1, …, yn} and let ŷ = αeβx, then the value of α and β that minimize \sum{}(yi − ŷi)2 satisfy the following equations:

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Proof: The minimum is obtained when the first partial derivatives are 0. Let

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Thus we seek values for α and β such that \frac{\partial h}{\partial \alpha} = 0 and \frac{\partial h}{\partial \beta} = 0; i.e.

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Property 2: Under the same assumptions as Property 1, given initial guesses α0 and β0 forα  and β, let F = [f  g]T where f and g are as in Property 1 and

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Now define the 2 × 1 column vectors Bn and the 2 × 2 matrices Jn  recursively as follows

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Then provided α0 and β0 are sufficiently close to the coefficient values that minimize the sum of the deviations squared, then Bn converges to such coefficient values.

Proof: Now

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Thus

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The proof now follows by Property 2 of Newton’s Method.

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