6- Tucker
Tucker model is an N-way model. For a scientific overview of the method, click
here.
Some specifications:
- "Num.factors"
is the place where the user puts the N parameters.
The user has to write "-1"
when he does not want to reduce the correponding mode (Tucker2/1 ).
- "OK" button
executes Tucker model.A default plot is returned after run (unless an information
appears). The other plots are available in the menu "results".
- "bootstrap" button
excutes Tucker model on original and resampled (by bootstrap) data. The user
will obtain the same plot as preceeding, but with a bootstrap estimation of
stability of the model (convex hulls, etc...). Available only for 3D!
- "Preprocessing" button
opens a new window, see below.
- "Postprocessing"
button opens a new window, see below.
- "close" button closes the
window.
- Validation window:(Available
only for 3D!)The global stability of the model is estimated for different
parameters between
[1 1 1] and "num. factors" number. After having chosen the maximal
parameters, the user has to click on the "OK" button. A surface
is plotted .
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Submenus and sub-windows:
preprocess menu:
see parafac window.
post-processing window:
Tucker solutions are subspaces:we can
choose the basis of these subspaces , in order to have the most interpretable
solution. Basis can be found in order to maximise different criteria.
- maximise the diagonale of the core
(when the core is cubic)
- maximise the slice-wise diagonale of
the core (when the 2 first dimensions of the core are equal.
- maximise thesquared variance of the
core.
- No rotation:default, i.e. Singular
Value Decomposition of the columns of the loadings.
Tucker options:
It is used to affect parameters of the
Tucker algorithm.
Bootstrap options:
- Bootstrap model : naive (resampling
the horizontal slabs of X) and residual (resampling the horizontal slabs of
the residuals of Tucker(X)).
- Bootstrap replicates: Number of replicates.