Package jgpml.covariancefunctions
Class CovNNoneNoise
java.lang.Object
jgpml.covariancefunctions.CovNNoneNoise
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CovarianceFunction
Neural network covariance function with a single parameter for the distance
measure and white noise. The covariance function is parameterized as:
k(x^p,x^q) = sf2 * asin(x^p'*P*x^q / sqrt[(1+x^p'*P*x^p)*(1+x^q'*P*x^q)]) + s2 * \delta(p,q)
where the x^p and x^q vectors on the right hand side have an added extra bias entry with unit value. P is ell^-2 times the unit matrix and sf2 controls the signal variance. The hyperparameters are:
[ log(ell) log(sqrt(sf2) log(s2)]
For reson of speed consider to use this covariance function instead of CovSum(CovNNone,CovNoise)
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionJama.Matrixcompute(Jama.Matrix loghyper, Jama.Matrix X) Compute covariance matrix of a dataset XJama.Matrix[]compute(Jama.Matrix loghyper, Jama.Matrix X, Jama.Matrix Xstar) Compute compute test set covariancesJama.MatrixcomputeDerivatives(Jama.Matrix loghyper, Jama.Matrix X, int index) Coompute the derivatives of thisCovarianceFunctionwith respect to the hyperparameter with indexidxstatic voidintReturns the number of hyperparameters of thisCovarianceFunction
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Constructor Details
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CovNNoneNoise
public CovNNoneNoise()
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Method Details
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numParameters
public int numParameters()Returns the number of hyperparameters of thisCovarianceFunction- Specified by:
numParametersin interfaceCovarianceFunction- Returns:
- number of hyperparameters
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compute
public Jama.Matrix compute(Jama.Matrix loghyper, Jama.Matrix X) Compute covariance matrix of a dataset X- Specified by:
computein interfaceCovarianceFunction- Parameters:
loghyper- columnMatrixof hyperparametersX- input dataset- Returns:
- K covariance
Matrix
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compute
public Jama.Matrix[] compute(Jama.Matrix loghyper, Jama.Matrix X, Jama.Matrix Xstar) Compute compute test set covariances- Specified by:
computein interfaceCovarianceFunction- Parameters:
loghyper- columnMatrixof hyperparametersX- input datasetXstar- test set- Returns:
- [K(Xstar, Xstar) K(X,Xstar)]
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computeDerivatives
public Jama.Matrix computeDerivatives(Jama.Matrix loghyper, Jama.Matrix X, int index) Coompute the derivatives of thisCovarianceFunctionwith respect to the hyperparameter with indexidx- Specified by:
computeDerivativesin interfaceCovarianceFunction- Parameters:
loghyper- hyperparametersX- input datasetindex- hyperparameter index- Returns:
Matrixof derivatives
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main
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