法向回归 令s空艺 L-2--28 12--可-24-{②〔2） -2-可-2{2j ·则。-)+。-广+ 2I c2=s-c t lexu@mail.xidian.edu.cn ●● 矩阵论 11 lexu@mail.xidian.edu.cn 矩 阵 论 11 法向回归  令  则 ( ) ( )( ) ( ) 2 n nn 2 2 ss i i i i 1 i 1 i 1 n n nn st i i i i i i i 1 i 1 i1 i1 2 n nn 2 2 tt i i i i 1 i 1 i 1 1 l ss s s n 1 l s s t t st s t n 1 l tt t t n = = = = = = = = = =     = −= −            = − −= −            = −= −      ∑ ∑∑ ∑ ∑ ∑∑ ∑ ∑∑ n i i 1 1 s s n = = ∑ n i i 1 1 t t n = = ∑ ( ) ( ) 2 2 ss tt ss tt st 1 st 2 1 l l l l 4l c 2l c s ct  −+ − +  =    = −