k***s
发帖数: 206 | 1 If i have a feature expansion:
{0, 1}^n -> {0, 1}^2n. for example. If n = 3, then
Theta(x1,x2,x3) = (1, x1, x2, x3, x1x2, x1x3, x2x3, x1x2x3): Every possible
"logical OR" from these 3 variables (including 1).
In this case, show K(x,y) for Theta can be computed in polynomial time: poly
(n).
K(x,y) = Theta(x) dot product Theta(y).
这里Theta(y) 指的是什么？？？？ | j****a
发帖数: 1277 | 2 题目不是给出了么
possible
poly
【在 k***s 的大作中提到】
: If i have a feature expansion:
: {0, 1}^n -> {0, 1}^2n. for example. If n = 3, then
: Theta(x1,x2,x3) = (1, x1, x2, x3, x1x2, x1x3, x2x3, x1x2x3): Every possible
: "logical OR" from these 3 variables (including 1).
: In this case, show K(x,y) for Theta can be computed in polynomial time: poly
: (n).
: K(x,y) = Theta(x) dot product Theta(y).
: 这里Theta(y) 指的是什么？？？？
| K****n
发帖数: 5970 | 3 b = Theta(a) 就是 input a有 n维，output b有 2n维
写成 Theta(x1,x2,x3)可能只是直观说明 x=(x1,x2,x3)是三维
Theta(x) poly(n)
Theta(y) poly(n)
dot product poly(n)
然后一加还是poly(n)，可能是这个意思
possible
poly
【在 k***s 的大作中提到】
: If i have a feature expansion:
: {0, 1}^n -> {0, 1}^2n. for example. If n = 3, then
: Theta(x1,x2,x3) = (1, x1, x2, x3, x1x2, x1x3, x2x3, x1x2x3): Every possible
: "logical OR" from these 3 variables (including 1).
: In this case, show K(x,y) for Theta can be computed in polynomial time: poly
: (n).
: K(x,y) = Theta(x) dot product Theta(y).
: 这里Theta(y) 指的是什么？？？？
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