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Principal component analysis, a technique for dimensionality reduction.

1 vote
Accepted

Principle Component Analysis on multiple functions

Variations of PCA can still be applicable. If the data is not linear, use nonlinear PCA. It is not an issue there a multiple "y"s for every "x". PCA is unsupervised, there is no notion of targets. … In PCA, there are only dimensions. Typically, the dimensions are standardized so each dimension can be weighted independent of scale. One caveat - PCA is domain agnostic. …
Brian Spiering's user avatar
2 votes
Accepted

Ploting eigenvectors

The PCA projections do not look not orthogonal because your figure axes are not equal. …
Brian Spiering's user avatar
1 vote

PCA scikit-learn - ValueError: array must not contain infs or NaNs

From scikit-learn's PCA docs: When True (False by default) the components_ vectors are multiplied by the square root of n_samples… That creates an overflow issue which results in the ValueError …
Brian Spiering's user avatar
1 vote

Higher variance in PCA can mean, that data structure is less informative?

It is not the best use of Principal Component Analysis (PCA) to compare information loss for different data structures. It would be more appropriate to use Information Theory. …
Brian Spiering's user avatar
1 vote

t-SNE on extremely high-dimensional spaces

There is no theoretical upper bound for t-SNE. However, pragmatically it will become increasingly computationally impracticable to reduce higher and higher dimensions to lower and lower dimensions. Th …
Brian Spiering's user avatar
0 votes

How to tell how much information I lose when I simplify the graph data structure with respec...

Graph comparisons can be tricky. One option is to take an Information Theory approach, something like "An information-theoretic, all-scales approach to comparing networks"
Brian Spiering's user avatar
1 vote
Accepted

Dimensionality reduction with prior knowledge of colinearity between features

One option is to use Multidimensional scaling (MDS) for dimensionality reduction. MDS can create a visualization of the relative positions for data based on the distance between the data points. In y …
Brian Spiering's user avatar
5 votes
Accepted

can I use t-sne or PCA to reduce number of classes?

No. t-Distributed Stochastic Neighbor Embedding (t-SNE) and Principal Component Analysis (PCA) are dimension reduction techniques, aka fewer columns of a tidy dataframe. …
Brian Spiering's user avatar
1 vote

Eigenvalues of covariance matrix are negative

That is probably a result of a floating point error. The matrix is 60,000 x 20 and sparse (mostly zeros). The result of the calculations are values very close to zero that are not correctly represente …
Brian Spiering's user avatar
0 votes

Practical Interpretation of PCAs for a supplier analysis

Principal Component Analysis (PCA) is not very useful for that type of interpretation. …
Brian Spiering's user avatar
1 vote

Should Principal components be normalized before applying K means on them?

No - There is no need to normalize after Principal Component Analysis (PCA) because each dimension is on the same scale. …
Brian Spiering's user avatar
1 vote

PCA huge parts of missing data filling

Principal component analysis (PCA) is not designed for time series data. It would be better to switch to singular spectrum analysis (SSA) which is designed for time series. …
Brian Spiering's user avatar
1 vote

How is PCA applied to (one-hot encoded) DNA sequence data?

The paper is incorrect in applying Principal Component Analysis (PCA) to boolean data since PCA implicitly minimizes a squared loss function, which is not always appropriate for not real-valued data. …
Brian Spiering's user avatar
2 votes

Distributed PCA or an equivalent

There is principal component analysis (PCA) in Spark's Machine Learning Library (MLlib). …
Brian Spiering's user avatar
2 votes

Using PCA as features for production

In scikit-learn, PCA has the fit_transform method which fits and applies the dimensionality reduction to the training data. There is also transform which only applies the dimensionality reduction. …
Brian Spiering's user avatar

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