matlab 求一个1*n阶矩阵的所有1*(n-1）阶子矩阵

matlab 求一个1*n阶矩阵的所有1*(n-1）阶子矩阵

其实就是一个简单的组合问题：
>> n=5;
>> A=rand(1,n)
A =
    0.8147    0.9058    0.1270    0.9134    0.6324
>> I=nchoosek(1:n,n-1);
>> B=A(I)
B =
    0.8147    0.9058    0.1270    0.9134
    0.8147    0.9058    0.1270    0.6324
    0.8147    0.9058    0.9134    0.6324
    0.8147    0.1270    0.9134    0.6324
    0.9058    0.1270    0.9134    0.6324B的每一行就是一个A的1x(n-1)阶子矩阵。

matlab中没有直接求伴随矩阵的函数，所以可以通过编写程序实现。可参照： function b = adj(a) %求伴随矩阵 %adj matrix adjoint. % adj(a) is the adjoint matrix of square matrix a. % it is computed using the cayley-hamilton theorem. % the inverse of a is: inv(a) = adj(a)/det(a). % % matrices that are not invertable still have an adjoint. %written by paul godfrey, april, 1998 %[email protected] ce = poly(eig(a)); cesize = max(size(ce)); p = [0 ce(1:(cesize-1))]; s = (-1)^(max(size(a))+1); b = s*polyvalm(p,a);