@proxify<EOL>def squared_error(x, rho, x_obs):
return (x + x_obs / rho) / (<NUM_LIT:1.> + <NUM_LIT:1.> / rho)<EOL>
Proximal operator for squared error (l2 or Fro. norm)

squared_error(x_obs)

Parameters
----------
x_obs : array_like
    Observed array or matrix that you want to stay close to