Embedding Dimension Time Series Calculator

Estimate embedding dimension from sampled series data. Review neighbor behavior, delay settings, and reconstructed vectors. Improve nonlinear analysis with practical outputs today.

Calculator Form

Example Data Table

Index Observed Value Delay Candidate Dimension
12.1012
22.5013
33.0014
43.8015
54.9016

Formula Used

This calculator uses the False Nearest Neighbors method. A scalar time series is reconstructed into vectors:

Y(i) = [x(i), x(i+τ), x(i+2τ), ..., x(i+(m-1)τ)]

Here, τ is the delay and m is the embedding dimension. For each point in dimension m, the nearest neighbor is found. Then the same pair is checked in dimension m+1.

A neighbor is marked false when the extra coordinate expands too much:

R = |x(i+mτ) - x(j+mτ)| / Dm

If R exceeds the relative threshold, or the expanded distance becomes too large compared with the series deviation, the neighbor is false. The suggested dimension is the first dimension where the false-neighbor percentage drops below the chosen target.

How to Use This Calculator

  1. Paste your time series values into the main field.
  2. Set a delay value. Start with 1 if unsure.
  3. Choose the maximum dimension to test.
  4. Adjust relative and absolute thresholds if needed.
  5. Select a distance metric for neighbor comparison.
  6. Enable normalization when values have large scale changes.
  7. Click the calculate button.
  8. Review the suggested embedding dimension and the FNN table.

About Embedding Dimension in Time Series Analysis

Why Embedding Dimension Matters

Embedding dimension helps rebuild hidden system dynamics from one measured signal. It supports phase space reconstruction for nonlinear analysis. A low dimension can fold trajectories together. A high dimension can add noise and computation. Good estimation improves forecasting, attractor study, and state-space modeling.

Using False Nearest Neighbors

The False Nearest Neighbors method checks whether close points remain close after one more delayed coordinate is added. If many neighbors separate strongly, the current dimension is too small. When the percentage falls, the geometry becomes more reliable. This makes the method practical for measured scientific and engineering series.

Choosing Delay and Thresholds

Delay controls how far apart coordinates are in reconstructed vectors. Very small delays can create redundant coordinates. Very large delays can destroy structure. Thresholds affect sensitivity. Stricter thresholds may suggest higher dimensions. Softer thresholds may reduce recommended dimensions. Analysts should test values that match signal noise and sampling quality.

Interpreting the Calculator Output

This calculator reports false-neighbor percentages across tested dimensions. It also gives a suggested embedding dimension based on a target limit. The preview table shows reconstructed vectors for quick inspection. Use these results with domain knowledge, especially for noisy, short, or strongly nonstationary signals. Recheck settings before making final modeling decisions.

Frequently Asked Questions

1. What does embedding dimension mean?

It is the number of delayed coordinates used to reconstruct a state space from one observed time series. It helps reveal the system structure.

2. What is a false nearest neighbor?

It is a point that looks close in a low dimension but separates after adding another coordinate. That indicates under-embedding.

3. Why should I choose a delay value?

Delay sets the spacing between coordinates in each reconstructed vector. It strongly affects redundancy and geometric separation.

4. What target FNN percent should I use?

Many users start with 5% or less. The right target depends on noise level, sample size, and analysis purpose.

5. Should I normalize the series first?

Normalization helps when values have large magnitudes or scale shifts. It can improve threshold interpretation and numerical stability.

6. Which distance metric is best?

Euclidean is the most common default. Manhattan and Chebyshev can be useful when you want different sensitivity to coordinate differences.

7. What happens if my series is too short?

Short series reduce usable vectors and weaken nearest-neighbor testing. Results may become unstable or insufficient for higher dimensions.

8. Can this result replace expert judgment?

No. It is a strong screening tool, but final dimension choice should also consider signal quality, delay selection, and domain context.

Related Calculators

Moving Average CalculatorSeasonal Decomposition ToolTrend Analysis CalculatorTime Series Forecast ToolPartial Autocorrelation ToolStationarity Test ToolADF Test CalculatorKPSS Test CalculatorHolt Linear TrendHolt Winters Tool

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.