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Issue 1453: MDS: fall back to SVD when the full similarity matrix is known #3141

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FlorianWilhelm
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The SVD method can now be used to calculate the metric MDS. In order to do this a new argument method which defaults to smacof and can be set to svd was introduced in the MDS estimator.
This was done in order to fix issue #1453.

K = -0.5*np.dot(H, np.dot(similarities**2, H))
w, V = np.linalg.eig(K)
# Sort eigenvalues and eigenvectors in decreasing order
ix = np.argsort(w)[::-1]
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w is already sorted by default, no?

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Addressed in my branch (else, no, but I've switched to sparse.linalg.eigs, which does).

@NelleV
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NelleV commented Apr 2, 2015

Here is a new PR : #4485

@amueller
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closing as replaced by #4485.

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