- x
a vector with times corresponding to the observations in the irregular initial time series

- xmin
the time corresponding to the first observation in the regular time series

- frequency
the frequency of observations in the regular time series

- deltat
the interval between two successive observations in the regular time series. This is the inverse of `frequency`

. Only one of both parameters need to be given. If both are provided, `frequency`

supersedes `deltat`

- tol
the tolerance in the difference between two matching observations (in the original irregular series and in the regulated series). If `tol=0`

both values must be strictly identical; a higher value for `tol`

allows some fuzzy matching. `tol`

must be a round fraction of `deltat`

and cannot be higher than it, otherwise, it is adjusted to the closest acceptable value. By default, `tol=deltat`

- tol.type
the type of window to use for the time-tolerance: `"left"`

, `"right"`

, `"both"`

(by default) or `"none"`

. If `tol.type="left"`

, corresponding `x`

values are seeked in a window ]xregul-tol, xregul]. If `tol.type="right"`

, they are seeked in the window [xregul, xregul+tol[. If `tol.type="both"`

, then they are seeked in the window ]xregul-tol, xregul+tol]. If several observations are in this window, the closest one is used. Finally, if `tol.type="none"`

, then *all* observations in the regulated time series are interpolated (even if exactly matching observations exist!)

- nclass
the number of classes to compute in the histogram. This is indicative, and will be adjusted by the algorithm to produce a nicely-formatted histogram. The default value is `nclass=50`

. It is acceptable in many cases, but if the histogram is not correct, try a larger value

- col
the three colors to use to represent respectively the fist bar (exact coincidence), the middle bars (coincidence in a certain tolerance window) and the last bar (values always interpolated). By default, `col=c(4,5,2)`

- xlab
the label of the x-axis

- ylab
the label of the y-axis

- main
the main title of the graph

- plotit
if `plotit=TRUE`

then the histogram is plotted. Otherwise, it is only calculated

- ...
additional graph parameters for the histogram