Function gethani determines a bandwidth that leads to, for the specified kernel, a variance reduction for a non-adaptive kernel estimate by a factor of value.
getvofh calculates the sum of location weights for a given bandwidth vector and kernel.
sofmchi precomputes the variance of a non-central chi distribution
with 2*L degrees of freedom as a function of the noncentrality parameter for an interval c(0,to).
Functions residualVariance and residualSpatialCorr are
used in package fmri to calculate variances and spatial correlations from residual objects.
gethani(x, y, lkern, value, wght, eps = 0.01)
getvofh(bw, lkern, wght)
sofmchi(L, to = 50, delta = 0.01)
residualVariance(residuals, mask, resscale = 1, compact = FALSE)
residualSpatialCorr(residuals, mask, lags = c(5, 5, 3), compact = FALSE)gethani returns a vector of bandwidths,
getvofh returns the variance reduction that would be obtained with a kernel estimate employing the specified kernel and bandwidth,
sofmchi returns a list with, e.g., components ncp and s2 containing vectors of noncentralityparameter values and corresponding variances, respectively, for the specified noncentral Chi distribution,
residualVariance returns a vector (compact==TRUE) or array(compact==FALSE) of voxelwise residual variances,
residualSpatialCorr returns an array of dimension lags
containing spatial correlations.
lower bound of search interval
upper bound of search interval
code for location kernel
target sum of location weights
relative size of voxel dimensions c(0,0) for 1D and c(w1,0)
for 2D problems.
attempted precision for bandwidth search
vector of bandwidths, length equal to 1,2 or 3 depending on the dimensionality of the problem.
number of effective coils, 2*L is the degree of freedom of the non-central chi distribution.
upper interval bound.
discretization width.
array of residuals, ifcompact only containing voxel with mask, otherwise for complete data cubes.
mask of active voxel (e.g. brain masks)
scale for residuals (residuals may be scaled for optimal integer*2 storage)
logical, determines if only information for voxel within mask or full for full data cubes is given.
positive integer vector of length 3, maximum lags for spatial correlations for each coordinate direction to be computed
Joerg Polzehl polzehl@wias-berlin.de
These are auxiliary functions not to be used by the user. They are only exported to be available for internal use in packages fmri, dti, qMRI and adimpro.