homework 4, problem 1 hint

[percy...@gmail.com]

Instead of the given hint, consider s_{ij} = s_{i(j-1)} and (z_{ij} or
(not x_{ij})).

[Cohan Sujay Carlos]

Percy,

 

Should the product on the RHS be over E_j to the power of x_j or is the Xi to be taken as a vector in the product?

 

Cohan
 

[Percy Liang]

In the first paragraph, we are talking about the distribution over a
binary vector x, in which case x_j is a scalar.

In the second paragraph, each data point x_i is a vector, so x_{ij}
is a scalar.

[Ning]

A silly question: what's the meaning of that inverse V sign in the
definition of s_ij?

[Percy Liang]

V means or.

[Jeffrey Regier]

Since s_{ij} is defined recursively, doesn't a base case also need to be specified? Would s_{i0} = 1?
 

Thanks.

 

On 10/24/07, percy...@gmail.com <percy...@gmail.com> wrote:

[Percy Liang]

Yes.

[Ankit Jain]

Where are the parenthesis in this equation? is it s_{ij} =
s_{i(j-1)} and [(z_{ij} or (not x_{ij}))]. OR s_{ij} = [s_{i(j-1)}

and (z_{ij}] or (not x_{ij})).

--ankit

On Oct 24, 4:07 pm, percyli...@gmail.com wrote:

[Percy Liang]

The former.

[OzenHaman]

The upside down V in the RHS means "AND" (an upright V is "OR").

So it's S_ij = z_i1 AND ... AND z_ij

-Omer