Re: [問題] Homework 3-1,3-2

[mengjia (try it)]

※ 引述《hometoofar (家太遠了)》之銘言：
: I am stuck on question 1 and 2 for homework 3 for a long time.
: Could someone give me a hint on them or point out if I am thinking in the
: right direction?
: For Q1, I try to expand the exponent in terms of xi1,xi2,xj1 and xj2 then I
: try to rearrange them so the expanded terms (other than the square of of the
: basic elements) fit well in the denomenator (n) of the infinite series
: e^n = (1+n/1!+n^2/2!+.......).  No luck on this direction so far...
: I couldn't get something like what we have in the lecture.
Try to expand the term e^[-r<xi-xj,xi-xj>] and find out phi(x).
It's harder than that in the lecture ... but just need a trick.

: For Q2, suppose x is in n1 space and phi(x) is in n2 space; we need to
: express n2 in terms of n1 and maybe d (the exponent in poly kernel), right?
To decide the dimension of space of phi(x) in any proper a,b,d,and xE(R^n).

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I still do my homework, so I can't make sure if Q1's hint is right .
I have get something that may be right. If I know some mistakes happen,
I will revise them quickly.


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◆ From: 140.112.4.240
→ hometoofar:I think I get it now, thanks.  Now stuck on Q3..
→ hometoofar:I get Q3 down to minimizing the dual, but having
→ hometoofar:trouble of solving 4 alphas with 2 equations...
推 Evenroll:do you already solve the primal?
→ hometoofar:Not really.. Let's talk about that in a new thread.