The Proximity Operator of a Function with Multiple Affine MappingProximal mapping for composition of...

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The Proximity Operator of a Function with Multiple Affine Mapping


Proximal mapping for composition of functionsProximal functionsProximal mapping of $f(U) = -log det(U)$Proof of convergence for the proximal point algorithmWhen is a mapping the proximity operator of some convex function?Does the linear transformation that a matrix encodes depend on a choice of basis?How to derive the proximal operator of the Euclidian norm?How to Do Backtracking Line Search for Proximal Gradient Decent?Low-rank matrix satisfying linear constraints linear mappingProximal Mappings intuition and practical example













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Let $f(mathbf{x}) = g(mathbf{A}mathbf{x})$, where $mathbf{A} in mathbb{R}^{M times N}$ is a linear transformation satisfying $mathbf{A}mathbf{A}^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$,
begin{equation}
text{prox}_f (mathbf{x}) = mathbf{x} + mathbf{A}^T (text{prox}_g(mathbf{Ax}) − mathbf{Ax}).
end{equation}



Now, if $f(mathbf{x}) = sum_{p=1}^{P} g(mathbf{A}_pmathbf{x})$, where $mathbf{A}_p in mathbb{R}^{M times N}$ are multiple linear trasformations satisfying $mathbf{A}_pmathbf{A}_p^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$, what would be the proximal mapping for the new $f(mathbf{x})$?.










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    0












    $begingroup$


    Let $f(mathbf{x}) = g(mathbf{A}mathbf{x})$, where $mathbf{A} in mathbb{R}^{M times N}$ is a linear transformation satisfying $mathbf{A}mathbf{A}^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$,
    begin{equation}
    text{prox}_f (mathbf{x}) = mathbf{x} + mathbf{A}^T (text{prox}_g(mathbf{Ax}) − mathbf{Ax}).
    end{equation}



    Now, if $f(mathbf{x}) = sum_{p=1}^{P} g(mathbf{A}_pmathbf{x})$, where $mathbf{A}_p in mathbb{R}^{M times N}$ are multiple linear trasformations satisfying $mathbf{A}_pmathbf{A}_p^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$, what would be the proximal mapping for the new $f(mathbf{x})$?.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Let $f(mathbf{x}) = g(mathbf{A}mathbf{x})$, where $mathbf{A} in mathbb{R}^{M times N}$ is a linear transformation satisfying $mathbf{A}mathbf{A}^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$,
      begin{equation}
      text{prox}_f (mathbf{x}) = mathbf{x} + mathbf{A}^T (text{prox}_g(mathbf{Ax}) − mathbf{Ax}).
      end{equation}



      Now, if $f(mathbf{x}) = sum_{p=1}^{P} g(mathbf{A}_pmathbf{x})$, where $mathbf{A}_p in mathbb{R}^{M times N}$ are multiple linear trasformations satisfying $mathbf{A}_pmathbf{A}_p^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$, what would be the proximal mapping for the new $f(mathbf{x})$?.










      share|cite|improve this question









      $endgroup$




      Let $f(mathbf{x}) = g(mathbf{A}mathbf{x})$, where $mathbf{A} in mathbb{R}^{M times N}$ is a linear transformation satisfying $mathbf{A}mathbf{A}^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$,
      begin{equation}
      text{prox}_f (mathbf{x}) = mathbf{x} + mathbf{A}^T (text{prox}_g(mathbf{Ax}) − mathbf{Ax}).
      end{equation}



      Now, if $f(mathbf{x}) = sum_{p=1}^{P} g(mathbf{A}_pmathbf{x})$, where $mathbf{A}_p in mathbb{R}^{M times N}$ are multiple linear trasformations satisfying $mathbf{A}_pmathbf{A}_p^T = mathbf{I}$. Then for any $mathbf{x} in mathbb{R}^{N}$, what would be the proximal mapping for the new $f(mathbf{x})$?.







      linear-algebra optimization convex-analysis






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      asked Mar 18 at 14:07









      Héctor Miguel Vargas GarcíaHéctor Miguel Vargas García

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          Even in the simpler case where $P=2$ and $A_1=A_2= textbf{I}$, there does not exist a closed form solution for the proximal operator of the sum. If you are interested in solving an optimization problem check the keywords "Douglas-Rachford" and "splitting".






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            Even in the simpler case where $P=2$ and $A_1=A_2= textbf{I}$, there does not exist a closed form solution for the proximal operator of the sum. If you are interested in solving an optimization problem check the keywords "Douglas-Rachford" and "splitting".






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              Even in the simpler case where $P=2$ and $A_1=A_2= textbf{I}$, there does not exist a closed form solution for the proximal operator of the sum. If you are interested in solving an optimization problem check the keywords "Douglas-Rachford" and "splitting".






              share|cite|improve this answer









              $endgroup$
















                0












                0








                0





                $begingroup$

                Even in the simpler case where $P=2$ and $A_1=A_2= textbf{I}$, there does not exist a closed form solution for the proximal operator of the sum. If you are interested in solving an optimization problem check the keywords "Douglas-Rachford" and "splitting".






                share|cite|improve this answer









                $endgroup$



                Even in the simpler case where $P=2$ and $A_1=A_2= textbf{I}$, there does not exist a closed form solution for the proximal operator of the sum. If you are interested in solving an optimization problem check the keywords "Douglas-Rachford" and "splitting".







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 2 days ago









                xelxel

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