Culegere de probleme de Analiz˘a numeric˘a
Culegere de probleme de Analiz˘a numeric˘a
Culegere de probleme de Analiz˘a numeric˘a
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8.2. B-spline 115<br />
B1,2(x) = ω1,2(x)B1,1(x)+(1−ω2,2(x))B2,1(x) = 1<br />
2 [(x−1)B1,1(x)+(4−x)B2,1(x)]<br />
B0,1(x) = xB0,0(x)+(2−x)B0,1(x)<br />
B1,1(x) = (x−1)B1,0(x)+(3−x)B2,0(x)<br />
B2,1(x) = (x−2)B2,0(x)+(4−x)B3,0(x)<br />
<br />
1 x ∈ [ti,ti+1)<br />
Bi,0(x) =<br />
<br />
0 în rest<br />
1 x ∈ [t0,t1) = [0,1)<br />
B0,0(x) =<br />
0 în rest<br />
<br />
1 x ∈ [1,2]<br />
B0,1(x) =<br />
0<br />
B3,3(x) = B0,3(x−3)<br />
⎧<br />
t<br />
⎪⎨<br />
B0,3(x) =<br />
⎪⎩<br />
3<br />
x ∈ [0,1)<br />
6<br />
Problema 8.2.2 Fie acum nodurile<br />
1<br />
6 (−3t3 +12t2 −12t+4) x ∈ [1,2)<br />
1<br />
6 (3t3 −24t2 +60t−44) 2 ≤ t < 3<br />
1<br />
6 (4−t)3 3 ≤ t < 4<br />
Să se <strong>de</strong>termine B-splinele Bi,k pentru k = 2 s¸i S∆f s¸i pentru f ∈ C 2 [0,3],<br />
R∆f.<br />
Solut¸ie. n+k = 7, n = 5<br />
n−1<br />
(S∆f)(x) = Bi,k(x)f(ξi)<br />
i=0<br />
ξi = ti+1<br />
Bi,2<br />
+···+ti+k<br />
k<br />
i = 0,n−1 i = 0,4<br />
x−ti<br />
ti+k−ti ωi,k(x) =<br />
dacăti<br />
0<br />
< ti+k<br />
în rest<br />
.