> The Spider Objects

>            CHAIN object

>        A=CHAIN(I,H) returns a chain object initialized with
>         a cell array of algorithms I and (hyper)parameters H.

>        This is used to create a chain of algorithms, the output of one
>         is fed into the input of the next.

>        Examples: f=chain({fisher('output_rank=1;feat=5') knn});
>                  [r,a]=train(cv({f knn}),toy);
>                  get_mean(r)