文章对应视频讲解:(Jacobi)雅克比迭代法
一、Jacobi迭代法
n = 3 n=3 n=3 , 阶数为 3 时
A = ( a 11 a 12 a 13 a 21 a 22 a 23 a 31 a 32 a 33 ) , b = ( b 1 b 2 b 3 ) , A=\begin{pmatrix} a_{11} & a_{12} &a_{13}\\ a_{21} & a_{22} &a_{23}\\ a_{31} & a_{32} &a_{33}\\ \end{pmatrix} ,\quad b=\begin{pmatrix} b_1\\b_2\\ b_3 \end{pmatrix}, A=
a11a21a31a12a22a32a13a23a33
,b=
b1b2b3
,
Jacobi公式为
x 1 ( k + 1 ) = b 1 − a 12 x 2 ( k ) − a 13 x 3 ( k ) a 11 x 2 ( k + 1 ) = b 2 − a 21 x 1 ( k ) − a 23 x 3 ( k ) a 22 x 3 ( k + 1 ) = b 3 − a 31 x 1 ( k ) − a 32 x 2 ( k ) a 33 \begin{gathered} x_1^{(k+1)} =\frac{b_{1}-a_{12}x_{2}^{(k)}-a_{13}x_{3}^{(k)}}{a_{11}} \\ x_2^{(k+1)} =\frac{b_{2}-a_{21}x_{1}^{(k)}-a_{23}x_{3}^{(k)}}{a_{22}} \\ x_3^{(k+1)} =\frac{b_{3}-a_{31}x_{1}^{(k)}-a_{32}x_{2}^{(k)}}{a_{33}} \end{gathered} x1(k+1)=a11b1−a12x2(k)−a13x3(k)x2(k+1)=a22b2−a21x1(k)−a23x3(k)x3(k+1)=a33b3−a31x1(k)−a32x2(k)
由公式可以看出 ,每一次迭代的各个分量都是独立计算的,这也是为什么Jacobi迭代可以用于并行计算。
或等价的,将