FastIcaContrastFunction Enumeration

Enumerates the contrast functions used in ICA.

Definition

Namespace: Numerics.NET.Statistics.Multivariate
Assembly: Numerics.NET (in Numerics.NET.dll) Version: 9.1.5
C# 
public enum FastIcaContrastFunction

Remarks

The contrast function determines the nonlinearity applied during the fixed-point iteration in the FastICA algorithm. Different choices affect robustness and convergence speed.

  • LogCosh: Uses the hyperbolic tangent function, g(u) = tanh(αu). Suitable for most applications and robust to outliers.
  • Exponential: Uses g(u) = u * exp(-u² / 2). More sensitive to outliers, can be useful for super-Gaussian sources.
  • Cubic: Uses g(u) = u³. Simple and fast, but less robust to outliers.

Members

LogCosh0 LogCosh contrast function: g(u) = tanh(αu).

The default and recommended choice for most ICA problems. The parameter α controls the steepness of the nonlinearity.

Exponential1 Exponential contrast function: g(u) = u * exp(-u² / 2).

Useful for separating super-Gaussian sources. More sensitive to outliers.

Cubic2 Cubic contrast function: g(u) = u³.

Fast to compute, but less robust to outliers. Suitable for sub-Gaussian sources.

See Also