Re: [問題] max violating pair

作者: rafan (@_@"""")   2005-11-09 11:58:21
※ 引述《Evenroll (研二不是應該很清閒嗎?)》之銘言:
: I have a question about max violating pair.
: since
: I_up = {t| alpha_t < C, y_t = 1 or alpha_t > 0, y_t = -1 }
: and
: I_low = {t| alpha_t < C, y_t = -1 or alpha_t > 0, y_t = 1 }
: then
: at begining, alpha is set to zero as a initial value
: then all i don't belong to I_up or I_low, since no alpha_i > 0.
: should I just randomly pick up 2 index i & j ?
Hey! If alpha_i = 0 and y_i = 1, then it is in I_up
(alpha_i = 0 < C).
: if I just randomly choose i & j at the first iteration,
: I still encounter this problem at the second iteration,
: since only alph_i and alpha_j are changed,
: all other i are still zero and they don't belong to I_up or I_low...
: so...
: I think that in the definition of I_up and I_low,
: maybe we should rewrite the inequality to be alpha_t >= 0 or alpha_t <= C
: is that right?
作者: Evenroll (怎樣才能充滿活力?)   2005-11-09 12:33:00
I see, thank you:)

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