Questions tagged [decomposition]

Decomposition might refer to Time Series Decomposition. Decomposing a time-series into Seasonal and Trend components can be achieved by using several methods, such as STL (which uses a Loess smoothing algorithm).

Prefer using if applicable.


Time series data can exhibit a variety of patterns, and it is often helpful to split a time series into several components, each representing an underlying pattern category.

There are three types of time series patterns: trend, seasonality and cycles. When we decompose a time series into components, we usually combine the trend and cycle into a single trend-cycle component (often just called the trend for simplicity). Thus we can think of a time series as comprising three components: a trend-cycle component, a seasonal component, and a remainder component (containing anything else in the time series). For some time series (e.g., those that are observed at least daily), there can be more than one seasonal component, corresponding to the different seasonal periods.

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Is there Fortran subroutine in LAPACK/BLAS or somewhere else to calculate LDL decomposition?

Like the title says, I need to form cholesky LDL decomposition for my positive definite matrix A (Like normal cholesky, but there's ones one diagonal of L, and D is diagonal matrix). I have found only one function in Lapack which does that, but it…
Jouni
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Can anyone explain the anomalous behavior of LU decomposition in Revol R?

A simple matrix benchmark test has indicated that Revolution Analytics R 2.13.2's LU decomposition is nearly 5 times slower than matrix multiplication. Theory and many years of practice show that LU should be 1/3 to 2/3 the time for A*A. Revo R and…
Derek O'Connor
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How to decompose table with reference to Heath's Theorem? [Homework]

I have a general understanding of Heath Theorem but I'm having trouble getting my head around this question: Use the functional dependencies to carry out a non-loss decomposition in line with Heath’s Theorem, to produce a set of tables in 3NF (3 rd…
jim
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Helmholtz decomposition of a vector field in Fourier space with Python

I have a 3D vector field and I want to extract its divergence-free part (also called transverse component), using the Helmholtz decomposition. In principle, this can be done in the Fourier space, as illustrated here in the proof. I wrote this Python…
Wil
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Seasonal component inconsistency in X-11 method using R

I am learning about time series decomposition using the X-11 method in R. I am following the book “Forecasting: Principles and Practice (3rd ed)” by Rob J Hyndman and George Athanasopoulos, which uses the seasonal package to perform seasonal…
Rony Golder
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TypeError: seasonal_decompose() got an unexpected keyword argument 'period'

I'm trying to digest time series data with datetime index. I'm going to use period in my project, but it gives me an error saying there is no argument named period. I couldn't find anything for that. But I see that the interval is mentioned on the…
Sattawat
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How to plot ICA components extracted from EEG signal?

I'm following the answer to this question and this scikit-learn tutorial to remove artifacts from an EEG signal. They seem simple enough, and I'm surely missing something obvious here. The components extracted don't have the same length as my…
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PostgreSQL query decomposition

I fail to decompose simple SQL queries. I use PostgreSQL but my question is also related to other RDBMS. Consider the following example. We have table orders and we want to find first order after which total amount exceeded some limit: drop table if…
dvv
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Inverse stationary wavelet transform with pywavelets

I am trying to reconstruct the approximations and details at all levels using the inverse stationary wavelet transform from the by wavelets package in python. My code is the following: def UDWT(Btotal, wname, Lps, Hps, edge_eff): Br = …
jokerp
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Database extraneous attributes and decomposition

I am kind of confused on the notion of extraneous attributes and a proper decomposition into 3NF. For example, I have the following relation: r(A,B,C,D,E,F) F = FD's F = {A-> BCD, BC-> DE, B->D, D->A} I want to compute the canonical cover in order…
Eric
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Pygame-Space invaders bullets

I'm sorry for editing this question. I really have a hard time explaining my question because this thing is really nerve wracking. I started about 3 weeks ago and my mind is already exploding. To summarize what I want, this is the code right…
HEL
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Accessing branch-and-cut node id in generic Cplex callback

I have an optimization problem that is decomposed using Benders decomposition. I implemented a Cplex generic callback (in JAVA) that includes Lazy, User and Heuristic callbacks. Now, I need to add some cut management strategies e.g., limiting the…
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How to force python to perform an LU decomposition without a permutation

In MATLAB, it is possible to use a hack to force the builtin LU decomposition algorithm to not use a permutation matrix (i.e., force P=I), as shown here. Is there a similar hack in python? Namely, is there any way to force scipy.linalg.lu (or any…
Oren Milman
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2D matrix decomposition with negative scale

I have a 2d matrix created from position, scale and rotation (no skew). I would like to be able to decompose this matrix back to the original components and have managed to do so with the following pseudo code: posX = matrix.tx posY =…
NoOdle
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Finding a tree decomposition of a graph in Python

I need an algorithm that can find a tree decomposition given a graph in Python, the graphs will be small so it doesn't need to be very efficient. I have looked around but cannot find much on this at all. Anyone know of a package that can do this or…