# Mathematical equations of PLS and PLS-DA models

Submitted by joseacayu on 25 August 2016 - 7:45am

Forums:

Please, can someone provide some indication to the two topics following which I can not clarify?

- How can I see the mathematical equation of a PLS model in The Unscrumbler 9.7

- How can I see the mathematical equation of a PLS-DA model in PLS-Toolbox

Any suggestions will be welcome. Thank you at all.

José A. Cayuela

hlmark

25 Aug 2016

Jose - it's not clear what you are asking for. The derivations and expressions for the equations describing PLS are available in numerous books, but require matrix math and matrix equations which are not easily presented otherwise. Unscrambler is a software package that implements those equations, but whle there are tutorial books specifically for Unscrambler that describe the underlying math, the software itself is not intended to be a mathematical tutorial. If this doesn't answer your questions, then please be more specific as to the information you are looking for.

Howard

\o/

/_\

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joseacayu

25 Aug 2016

Dear Howard, thank you very much for answer.

I built PLS models by using The Unscrumbler, now (Reviewers of a manuscript ask for this) I need print or see the mathematical equation. I understand it should be the generic type Y = TB+F, according to the Reference Method of The Unscrambler (where I do not find information for seeing practical model equations).

Analogous problem with PLS-DA models made by using PLS-Toolbox. I think in this case Matlab can provide easy solution ... but unfortunately I do not know Matlab!

If you know any approach to the solution it will be a happy new, thank you very much anyway.

Best regards,

José A.

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dangdk

25 Aug 2016

Hi Jose,

I do not know about Unscrambler 9.7 but in 10 you can see the regression vector of the model.

Regards

Dan

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joseacayu

25 Aug 2016

Hi Dan,

Thank you for the answer. Do you remember what menu option provides this?

Regards

J.A.

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joseacayu

25 Aug 2016

Hi Dan,

Thank you for the answer. Do you remember what menu option provides this?

Regards

J.A.

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ptillmann

26 Aug 2016

Jose,

when you finished the calibration development a screen apears with 4 graphs. The top right graph is the b vector. For a numerical diplay you need to change View to "numeric" (right clck on graph).

The formular is then:

y_pred = b_0 + sum(lamba_i * b_i)

with

b_0: b0 from Unscrambler (see top right quarter)

b_i: ith elemnt of b vector

lamba_i: y value of math treated spectrum at datapoint i

i = 1- n datapoints

The graph will also apear if you open an existing PLS model.

Peter

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joseacayu

30 Aug 2016

Hi Peter,

Thank you very much sincerely!

Jose A.

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ForestBiotech

08 Feb 2017

Hi All

I've the same question, but for Thermo microPHAZIR Software

Thank in advance

Jorge G.

---------------------------------------------------Jorge M. González Campos

Instituto Forestal (INFOR). Chile

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