[ntimes,vals,labs] = apenhr(times,vals,labels,[rstd lag]);
times
|
A column vector of times at which each val is measured.
|
vals
| A column vector of data. |
labels
| A column vector of labels indicated whether the data are valid. 1 indicates valid data, 0 indicates invalid data. |
rstd
|
The "filter factor" in ApEn. If this is positive, it will be
multiplied by the standard deviation of vals
(after invalid points are deleted) to set the ApEn filter factor.
If rstd is negative, its absolute value will be
used directly as the ApEn filter factor. The default value is 0.2
(which will be multiplied by the standard deviation of the data).
|
lag
| The embedding lag. In Kaplan et al., this is set to one beat. |
ntimes
| The min and max time of the segment being analyzed. |
nval
| The approximate entropy of this segment. |
labels
| The fraction of the data that was valid. |
apenhr implements the ApEn calculation for heart rate,
using the standard parameter values: an embedding dimension of 2
and an embedding lag of 1 sample. (If heart rate is being analyzed,
the literature suggests that
it should be arranged to have a sampling interval of roughly 0.8 secs.)
The program carries out the embedding steps etc. detailed in the
documentation for apen.
Invalid data are eliminated from the calculation after the embedding has been performed, so that only completely valid vectors are used.
apen.