Structured PCA Model
XThe matrix of data
nThe number of samples
kLatent dimensionality
dSimensionality of observations
betaCovariance function hyperparameters
Kcovariance matrix generated from the covariance function and hyperparameters
KDPartial derivatived of K w.r.t each of the hyperparameters
locsLocations (t_i)
covFnCovariance function
covFnDFunction giving partial derivatives of covariance function w.r.t hyperparameters
muHatMAP estimate of mu
WHatMAP estimate of W
sigSqHatMAP estimate of sigSq
VmeanThe posterior mean of each latent variable
VVarThe posterior variance around each latent variable
logEvidencelog of the approximate evidence
logPosteriorssequence of posteriors obtained in fitting. Un-normalised if sparse
logEvidenceDPartial derivatives of evidence w.r.t hyperparameters
HThe precision matrix for the gaussian approximation to the posterior around each w
maximthe maximisation object returned in hyperparameter tuning
thetaConvWhether theta has been optimised to convergence (if false, beta has probably converged, not theta)
thetabetaHist history of betas in optimisation
convergenceHistory of logEvidence and logPosteror; used to assess convergence
sparsewhether this is a sparse stpca model
bThe sparsity hyperparameter in a sparse model.
crossvalidate(nFolds = 3, nThreads = 1)Perform k-fold cross-validation (possibly multithreaded) to determine the held out log likelihood of examples. This could be used as an alternative to computing the approximate evidence in model selection.
decode(Vnew)Decode points in the latent space into observations
encode(Xnew)Encode a matrix of observations into latent distributions.
set_b(bNew)Setter for 'b'
set_beta(betaNew)Sets beta to a new value, recomputes K, KD and H.
set_locs(locsNew)Sets the locations, and recomputes K. Be careful with this method. Does not update theta
set_sparse(spNew, b)Setter for 'sparse'
set_X(Xnew)Sets X, updates mu. Does not opdate anything else so it is recommended to call update() or something. Be careful with this method.
simulate(n = 1, Wknown = TRUE)Simulates new synthetic data from a fitted model.
update(tune.maxit = 10, tune.tol = 1e-05, EM.maxit = 500,
EM.bftol = 1e-05, ...)The major method for performing inference. This iterates between updating theta (using update_theta) and updating beta (using update_beta).
update_beta(...)Optimises the approximate evidence with respect to the hyperparameters.
update_theta(maxit = 500, bftol = 1e-05)Finds the MAP theta using EM.
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