Algorithm to compute the elastic net estimator












0












$begingroup$


i'm interested in finding:
begin{align*}
beta_{*} in underset{beta in mathbb{R}^d}{argmin}big{
| Y-Xbeta |_{2}^2 + lambda | beta |_{2}^2 + mu | beta |_{1} big}
end{align*}

i did so by finding the minimum of $beta_j mapsto mathcal{L}(beta_1,...,beta_j,...,beta_d)$, which is
begin{align*}
beta_j^{*}=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+
end{align*}

where $v_j=X_j'(Y-sum_{substack{i=1 \ i neq j}}^dbeta_i X_i)$.
but now i'm struggling to write an algorithm to compute $beta_*$.
Should the algorithm be like this:

repeat until convergence:

for j=1:d
$beta_j=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+$

endfor

Thank you in advance










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$endgroup$












  • $begingroup$
    You could also solve this optimization problem using the proximal gradient method (or an accelerated proximal gradient method such as FISTA).
    $endgroup$
    – littleO
    Dec 28 '18 at 13:48
















0












$begingroup$


i'm interested in finding:
begin{align*}
beta_{*} in underset{beta in mathbb{R}^d}{argmin}big{
| Y-Xbeta |_{2}^2 + lambda | beta |_{2}^2 + mu | beta |_{1} big}
end{align*}

i did so by finding the minimum of $beta_j mapsto mathcal{L}(beta_1,...,beta_j,...,beta_d)$, which is
begin{align*}
beta_j^{*}=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+
end{align*}

where $v_j=X_j'(Y-sum_{substack{i=1 \ i neq j}}^dbeta_i X_i)$.
but now i'm struggling to write an algorithm to compute $beta_*$.
Should the algorithm be like this:

repeat until convergence:

for j=1:d
$beta_j=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+$

endfor

Thank you in advance










share|cite|improve this question









$endgroup$












  • $begingroup$
    You could also solve this optimization problem using the proximal gradient method (or an accelerated proximal gradient method such as FISTA).
    $endgroup$
    – littleO
    Dec 28 '18 at 13:48














0












0








0





$begingroup$


i'm interested in finding:
begin{align*}
beta_{*} in underset{beta in mathbb{R}^d}{argmin}big{
| Y-Xbeta |_{2}^2 + lambda | beta |_{2}^2 + mu | beta |_{1} big}
end{align*}

i did so by finding the minimum of $beta_j mapsto mathcal{L}(beta_1,...,beta_j,...,beta_d)$, which is
begin{align*}
beta_j^{*}=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+
end{align*}

where $v_j=X_j'(Y-sum_{substack{i=1 \ i neq j}}^dbeta_i X_i)$.
but now i'm struggling to write an algorithm to compute $beta_*$.
Should the algorithm be like this:

repeat until convergence:

for j=1:d
$beta_j=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+$

endfor

Thank you in advance










share|cite|improve this question









$endgroup$




i'm interested in finding:
begin{align*}
beta_{*} in underset{beta in mathbb{R}^d}{argmin}big{
| Y-Xbeta |_{2}^2 + lambda | beta |_{2}^2 + mu | beta |_{1} big}
end{align*}

i did so by finding the minimum of $beta_j mapsto mathcal{L}(beta_1,...,beta_j,...,beta_d)$, which is
begin{align*}
beta_j^{*}=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+
end{align*}

where $v_j=X_j'(Y-sum_{substack{i=1 \ i neq j}}^dbeta_i X_i)$.
but now i'm struggling to write an algorithm to compute $beta_*$.
Should the algorithm be like this:

repeat until convergence:

for j=1:d
$beta_j=frac{v_j}{1+lambda}big(1 - frac{mu}{2left|v_jright|}big)_+$

endfor

Thank you in advance







statistics regression machine-learning






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asked Dec 28 '18 at 13:39









yjntyjnt

113




113












  • $begingroup$
    You could also solve this optimization problem using the proximal gradient method (or an accelerated proximal gradient method such as FISTA).
    $endgroup$
    – littleO
    Dec 28 '18 at 13:48


















  • $begingroup$
    You could also solve this optimization problem using the proximal gradient method (or an accelerated proximal gradient method such as FISTA).
    $endgroup$
    – littleO
    Dec 28 '18 at 13:48
















$begingroup$
You could also solve this optimization problem using the proximal gradient method (or an accelerated proximal gradient method such as FISTA).
$endgroup$
– littleO
Dec 28 '18 at 13:48




$begingroup$
You could also solve this optimization problem using the proximal gradient method (or an accelerated proximal gradient method such as FISTA).
$endgroup$
– littleO
Dec 28 '18 at 13:48










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