mdcheck
Purpose
Missing Data Checker and infiller.
Synopsis
[flag,missmap,infilled] = mdcheck(data,options)
options = mdcheck('options')
Description
This function checks for missing data and infills it using a
PCA model if desired. The input is the data to be checked data as either a double
array or a dataset object. Optional input options is a structure containing options for how
the function is to run (see below).
Outputs are the fraction of missing data flag, a map of the locations
of the missing data as an unint8 variable missmap, and the data with the missing values filled
in infilled. Depending
on the plots option, a plot of the missing data may also be output.
Options
options = a structure array with the following fields:
frac_ssq: [{0.95}] desired fraction between 0 and 1 of
variance to be captured by the PCA model,
max_pcs: [{5}] maximum number of PCs in the model, if 0, then
it uses the mean,
meancenter: ['no'
| {'yes'}], tells whether to use mean centering in the algorithm,
recalcmean: ['no'
| {'yes'}], recalculate mean center after each cycle of replacement (may
improve results for small matricies),
display: [{'off'} | 'on'], governs level of display,
tolerance: [{1e-6
100}] convergence criteria, the first element is the minimum change and the
second is the maximum number of iterations,
max_missing: [{0.4}]
maximum fraction of missing data with which MDCHECK will operate, and
toomuch: [{'error'} | 'exclude'] what action should be taken
if too much missing data is found. 'error' exit with error message, 'exclude'
will exclude elements (rows/columns/slabs/etc) which contain too much missing
data from the data before replacement. 'exclude' requires a dataset object as
input for (data),
algorithm: [ {'svd'} | 'nipals' ] specified the missing
data algorithm to use, NIPALS typically used for large amounts of missing data
or large multi-way arrays.
Note: MDCHECK captures up to options.frac_ssq of the
variance using options.max_pcs or fewer PCA components.
The default options can be retreived using: options = mdcheck('options');.
See Also
parafac, pca
