reshape函数

reshape(X,M,N) or reshape(X,[M,N]) returns the M-by-N matrix whose elements are taken columnwise from X. An error results if X does not have M*N elements.

a = 0:2:11;           % [0     2     4     6     8    10]

b = reshape(a,2,3);   % [0     4     8
                      %  2     6    10]

c = [1 2;3 4];
d = reshape(c,4,1);  % [1
                     %  2
                     %  3
                     %  4]

randperm函数

randperm Random permutation.
P = randperm(N) returns a vector containing a random permutation of the integers 1:N. For example, randperm(6) might be [2 4 5 6 1 3].
P = randperm(N,K) returns a row vector containing K unique integers selected randomly from 1:N. For example, randperm(6,3) might be [4 2 5].

find函数

参考Matlab 之 find()函数