FIA data from Nrgaard & Ridder, Chemometrics & 
Intelligent Laboratory Systems, 1994, 23, 107-114

X contains the 12 x 100 x 89 spectral FIA data in 
a 12 x 8900 matrix. To convert to a three-way array 
in MATLAB 5 and higher type <X = reshape(X,DimX)>.
The concentrations of the three analytes are provided
in y

Xs is a set of three pure samples averaged from 
triplicate measurements. ys holds the concentrations

DimX gives the dimensions of the three-way array

For further info see above reference or
http://www.models.kvl.dk/users/rasmus/