( ). . , , .
, .
() .
, , . , 1 .
, .
.
1 = 8 .
, 256 (256=28).
: (, ), (, ), (, ), (, ), (, ).
1 = 1024 = 210 (1024) .
1 = 1024 = 220 (10242) .
1 = 1024 = 230 (10243) .
1 = 1024 = 240 (10244) .
1 = 1024 = 250 (10245) .
, ( ), . .
, .
() a. H(a).
b Ib(a), , ( b) Hb(a).
Ib(a) , b, Ib(a)=H(a)-Hb(a), .. .
, H(a) .
, , N , , :
i = - (p1*Log2p1+ p2*Log2p2+.+ pn*Log2pn) (1.3)
, n ,
p .
, . :
i = log2N(1.1)
, i ,
|
|
N .
N , i, , N.
(1.1) :
2I = N (1.2)
_1: 8 . . , ?
: , . , , 8 . ,
I = log2 8 = 3
_2: . . , ?
: . N=2, , I = log2 2 = 1 .
_3: , 50 , 25, 25
1) 50+25+25=100
2) 50/100=1/2, 25/100=1/4, 25/100=1/4
3)I= -(1/2 log21/2 + 1/4 log21/4 + 1/4 log21/4) = -(1/2(0-1) +1/4(0-2) +1/4(0-2)) = 1,5
_4: 16 . , ?
.. N = 16 , I = log2 N = log2 16 = 4 .