Ridge regression solution using matrix inverse

  • Context: Graduate 
  • Thread starter Thread starter ahmadnajeeb
  • Start date Start date
  • Tags Tags
    Optimization Square
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 4K views
ahmadnajeeb
Messages
1
Reaction score
0
Hi,
I want to know the solution of the following equation.
[tex] a = argmin_{a}[\sum{||a^Tx_i - y_i||^2}+\alpha ||a||^2] \\[/tex]
where [tex]x_i, y_i[/tex] are column vectors of dimensions m and n respectively where [tex]m>n[/tex]. [tex]\alpha[/tex] is a scalar and
[tex]Y = a^T X[/tex] where [tex]X=[x_1 x_2 ... x_k], Y = [y_1 y_2 ... y_k][/tex]

I know that without this constraint [tex]\alpha ||a||^2[/tex], its a simple least square optimization problem and I can solve it using Matlab's inverse operator. I want to use the same inverse operator but don't know how this constraint changes my original model.
 
Physics news on Phys.org
Sorry, but I'm curious- What is this? I don't recognize the aT thing or the double absolute value marks. Could you tell me what type of math is this? Is it Calculus III?
 
What matrix norm are you using for your constraint?