principal-components-analysis | Python/Numpy PCA using the transpose trick | Data Manipulation library
kandi X-RAY | principal-components-analysis Summary
kandi X-RAY | principal-components-analysis Summary
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- Compute the principal component of a matrix .
principal-components-analysis Key Features
principal-components-analysis Examples and Code Snippets
Community Discussions
Trending Discussions on principal-components-analysis
QUESTION
Two different methods of the principal component analysis were conducted to analyze the following data (ch082.dat) using the Box1's R-code, below.
https://drive.google.com/file/d/1xykl6ln-bUnXIs-jIA3n5S3XgHjQbkWB/view?usp=sharing
The first method uses the rotation matrix (See 'ans_mat' under the '#rotated data' of the Box1's code) and, the second method uses the 'pcomp' function (See 'rpca' under the '#rotated data' of the Box1's code).
However, there is a subtle discrepancy in the answer between the method using the rotation matrix and the method using the 'pcomp' function. make it match
My Question
What should I do so that the result of the rotation matrix -based method matches the result of the'pcomp' function?
As far as I've tried with various data, including other data, the actual discrepancies seem to be limited to scale shifts and mirroring transformations.
- The results of the rotation matrix -based method is shown in left panel.
- The results of the pcomp function -based method is shown in right panel.
Mirror inversion can be seen in "ch082.dat" data.(See Fig.1);
It seems that, in some j, the sign of the "jth eigenvector of the correlation matrix" and the sign of the "jth column of the output value of the prcomp function" may be reversed. If there is a degree of overlap in the eigenvalues, it is possible that the difference may be more complex than mirror inversion.
Fig.1
There is a scale shift for the Box2's data (See See Fig.2), despite the centralization and normalization to the data.
Fig.2
Box.1
...ANSWER
Answered 2020-Nov-16 at 16:00The two sets of results agree. First we can simplify your code a bit. You don't need your function or the for loop:
QUESTION
I have a simple R script for running FactoMineR's PCA on a tiny dataframe in order to find the cumulative percentage of variance explained for each variable:
...ANSWER
Answered 2017-Apr-11 at 20:36Thanks to Vlo, I learned that the differences between the FactoMineR PCA function and the sklearn PCA function is that the FactoMineR one scales the data by default. By simply adding a scaling function to my python code, I was able to reproduce the results.
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Install principal-components-analysis
You can use principal-components-analysis like any standard Python library. You will need to make sure that you have a development environment consisting of a Python distribution including header files, a compiler, pip, and git installed. Make sure that your pip, setuptools, and wheel are up to date. When using pip it is generally recommended to install packages in a virtual environment to avoid changes to the system.
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