A time series is kept as a data file on a computer storage device. The data file may contain samples obtained from an analog-to-digital converter or from a simulation program that solves difference or differential equations. A file should contain the number of samples, the sample time, identification strings and the sample values. For efficiency and accuracy reasons, the data is stored in their binary form (unformatted).
After invoking MLDK2, the user should specify the name of the data file. The data is then read into the -array. To scale the distances so that the maximum one will equal 1, the size of the attractor (assuming there is one) is estimated by the difference between the minimum and maximum value in the array. The values are transformed by the equations
The user specifies the values for the time delay, the ``Theiler
correction'', the norm,
the maximum embedding dimension,
the number of distances, the number of bins ,
the distance to be associated with the first bin boundary ()
and the name of the output file. The default value for is
determined by an estimate of the smallest distance likely
to be found5.1 at embedding dimension 1:
Since MLDK2FIT (see below) makes a plot of the correlation integrals, i.e. as a function of , we let the right (upper)
bin boundaries be given by
The array contains the sum of the logarithm of the distances that fall in a specific bin; the array contains the number of distances that fall in that bin and all ``lower'' ones.
At the end, the specified parameter values, the (, and ) arrays and the date of the experiment are written to the output file. This is a ``formatted'' one, since it must be transferred to the VAX via the network for post-processing by MLDK2FIT.