FAQ - Frequently Asked Questions
Please browse from the following list of FAQ items.
Topic: Importing / Exporting...
• After I upgraded PLS_Toolbox, my scripts which used MCR no longer work.
• Do I have to specify all the options to a function or only the ones that are
different from the defaults?
• How are the Q-residuals and Hotelling's T^2 (T2) values calculated
for PLS models?
• How do I automate PCA analysis for multiple images?
• How do I calculate my own T2 and Q limits?
• How do I calculate scores from a PLS or PLSDA model?
• How do I change the default options for a function?
• How do I interpret the Misclassification results reported by crossval?
• How do I make PlotGUI send its plot to a new figure and not overwrite the
• How do I make the plotscores commands shown at the end of the VARIMAX demo work?
• How do I manually calculate the limits for scores?
• How do I retrieve and display predictions from a model structure in the command
• How do I specify all options on the same line that contains the call to a
• How do I use specific known pure component spectra with MCR (Multivariate Curve
• How does PCA cross-validation work in PLS_Toolbox and Solo and how do I set up
the command-line options to best use it?
• I get an error message when I run NCROSSVAL which says that it can not find
NPROCESS or that there are too many inputs into NPREPROCESS
• I get an error message when I use plotscores with a scores matrix.
• Where do I find a description of the parafac2 constraints?
• Where do I find the regression vector (B) and regression intercept
(B0) for a PLS or PCR model?
• Where is the conpred1 function?
• Why do I get an error saying "Too Many Output Arguments" when using the
Mathworks' Neural Networks interface?
• Why do I get different cross-validation results from the command-line crossval
routine compared to the Analysis window?
• Why do I get different results when I preprocess before doing my
cross-validation vs. doing preprocessing inside crossval?
• Why does the PCAENGINE change the sign of the loadings returned by SVD?
• Why is my model built using command line functions different from the same one I
built in Analysis GUI?
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