Computing Correlation Dimension of Attractor | Hi, Explain?

In summary, the correlation dimension is a measure of the fractal structure of an attractor and can be computed without an explicit function by approximating the correlation integral directly from the data points.
  • #1
penguin007
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Hi,

I read that the dimension of an attractor is not necessarily an integer. I then tried to compute the dimension of the attractor defined by the system I’m studying but I found two definitions for the dimension: -The capacity dimension;
-The correlation dimension;
The second one is said to be easier to compute. However, I couldn’t do it because:
*the definitions I found lean on the existence of an explicit function, but I just have points given by the approached resolution of a differential system;
*they introduce a dimension m and then a limit when m tends to infinity (?).

Could anyone explain me what is the correlation dimension and how I can compute it without an explicit function??

Thanks in advance.
 
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  • #2
The correlation dimension is a measure of the fractal structure of an attractor. It is determined by calculating the correlation integral of the attractor, which measures the number of pairs of points whose distance is less than r. This correlation integral can be used to calculate the correlation dimension, which is the slope of the log-log plot of the correlation integral versus r. The correlation dimension is related to the fractal dimension, which is the degree of self-similarity of the attractor. To compute the correlation dimension without an explicit function, you will need to approximate the correlation integral directly from the data points given by the approached resolution of the differential system. For example, you can use the method developed by Grassberger and Procaccia (1983) to calculate the correlation integral. This method involves counting the number of pairs of points that are within a certain distance (r) of each other and then summing these up over a range of distances. The result is then used to calculate the correlation dimension.
 

1. What is the purpose of computing the correlation dimension of an attractor?

The correlation dimension of an attractor is a measure of its complexity and can provide insight into the underlying dynamics of a system. It is often used in the analysis of chaotic systems to determine the number of independent variables needed to accurately describe the system's evolution.

2. How is the correlation dimension of an attractor calculated?

The correlation dimension is calculated using the correlation integral, which is a measure of how the number of points in an attractor within a certain distance of each other changes as the distance decreases. This calculation involves plotting the logarithm of the correlation integral against the logarithm of the distance and determining the slope of the resulting line.

3. Can the correlation dimension of an attractor change over time?

Yes, the correlation dimension of an attractor can change over time as the underlying dynamics of the system evolve. It can also vary depending on the specific parameters used in the calculation, such as the embedding dimension and the distance threshold.

4. What are some applications of computing the correlation dimension of an attractor?

The correlation dimension has been used in a variety of fields, including physics, biology, and finance. It can help in the identification and characterization of chaotic systems, as well as in the prediction of future behavior. It has also been applied in the analysis of physiological data and in the study of complex systems.

5. Are there any limitations to using the correlation dimension to analyze an attractor?

While the correlation dimension can provide valuable insights into the complexity of a system, it is not a comprehensive measure and should be used in conjunction with other analysis techniques. It also requires careful selection of parameters and can be sensitive to noise in the data. Additionally, it may not be applicable to systems with non-uniformly sampled data or those with time-varying dynamics.

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