Re: [scikit-learn] unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Roman Yurchak
Ismael, as far as I saw the sklearn.decomposition.PCA doesn't mention scaling at all (except for the whiten parameter which is post-transformation scaling). So since it doesn't mention it, it makes sense that it doesn't do any scaling of the input. Same as np.linalg.svd. You can verify that

[scikit-learn] Question about LDA's coef_ attribute

2017-10-16 Thread Serafeim Loukas
Dear Scikit-learn community, Since the documentation of the LDA (http://scikit-learn.org/stable/modules/generated/sklearn.discriminant_analysis.LinearDiscriminantAnalysis.html ) is n

Re: [scikit-learn] Question about LDA's coef_ attribute

2017-10-16 Thread Alexandre Gramfort
no it stores the direction of the decision function to match the API of linear models. HTH Alex On Mon, Oct 16, 2017 at 3:27 PM, Serafeim Loukas wrote: > Dear Scikit-learn community, > > Since the documentation of the LDA > (http://scikit-learn.org/stable/modules/generated/sklearn.discriminant_a

Re: [scikit-learn] Question about LDA's coef_ attribute

2017-10-16 Thread Serafeim Loukas
Dear Alex, Thank you for the prompt response. Are the eigenvectors stored in some variable ? Does the lda.scalings_ attribute contain the eigenvectors ? Best, Serafeim > On 16 Oct 2017, at 16:57, Alexandre Gramfort > wrote: > > no it stores the direction of the decision function to match the

Re: [scikit-learn] unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Ismael Lemhadri
; Message-ID: <58c6d0da-9de5-4ef5-97c1-48159831f...@gmail.com> > Content-Type: text/plain; charset="us-ascii" > > Dear Scikit-learn community, > > Since the documentation of the LDA (http://scikit-learn.org/ > stable/modules/generated/sklearn.discriminant_analysis. &

Re: [scikit-learn] unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Roman Yurchak
On 16/10/17 17:16, Ismael Lemhadri wrote: My concern is actually not about not mentioning the scaling but about not mentioning the centering. That is, the sklearn PCA removes the mean but it does not mention it in the help file. I think it's currently assumed given the definition of the PCA, bu

Re: [scikit-learn] unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Andreas Mueller
earDiscriminantAnalysis.html> <http://scikit-learn.org/stable/modules/generated/sklearn.discriminant_analysis.LinearDiscriminantAnalysis.html <http://scikit-learn.org/stable/modules/generated/sklearn.discriminant_analysis.LinearDiscriminantAnalysis.html>>) is not so clear,

[scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Ismael Lemhadri
mail.python.org/mailman/listinfo/scikit-learn > > <https://mail.python.org/mailman/listinfo/scikit-learn> > > > > > > > > > > > -- > > > > Mes

Re: [scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Michael Eickenberg
> the PCA and np.linalg.svd give the same results. In academic >> > settings, >> > > students are often asked to compare different methods and to >> > check that >> > > they yield the same results. I expect that many students have >

Re: [scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Andreas Mueller
On 10/16/2017 02:27 PM, Ismael Lemhadri wrote: @Andreas Muller: My references do not assume centering, e.g. http://ufldl.stanford.edu/wiki/index.php/PCA any reference? It kinda does but is not very clear about it: This data has already been pre-processed so that each of the features\texts

Re: [scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Oliver Tomic
x27;s coef_ attribute > Message-ID: <58c6d0da-9de5-4ef5-97c1-48159831f...@gmail.com > <mailto:58c6d0da-9de5-4ef5-97c1-48159831f...@gmail.com>>; > Content-Type: text/plain; charset="us-ascii" > > Dear Scikit-learn community, &

Re: [scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Sebastian Raschka
t; -- > > > > Message: 3 > > Date: Mon, 16 Oct 2017 15:27:48 +0200 > > From: Serafeim Loukas mailto:seral...@gmail.com> > > <mailto:seral...@gmail.com <mailto:seral...@gmail.com>>> > > To: scikit-learn@pytho

Re: [scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Sebastian Raschka
t;> > > this problem before... >> > > Best, >> > > Ismael Lemhadri >> > > >> > > >> > > ___ >> > > scikit-learn mailing list >> > > scikit-l

[scikit-learn] Unclear help file about sklearn.decomposition.pca

2017-10-16 Thread Ismael Lemhadri
<http://www.springer.com/us/book/9780387310732> and Murphy > <https://mitpress.mit.edu/books/machine-learning-0> are pretty clear > that they subtract the mean (or assume zero mean) but don't standardize. > -- next part -- > An HTML attachment was scrubbed

Re: [scikit-learn] 1. Re: unclear help file for sklearn.decomposition.pca

2017-10-16 Thread Roman Yurchak
@gmail.com>>> > Content-Type: text/plain; charset="us-ascii" > > Dear Scikit-learn community, > > Since the documentation of the LDA > (http://scikit-learn.org/stable/modules/generated/sklearn.discriminant_analysis.LinearDiscrimi