@FUNCTION=interpolation
@SYNTAX=interpolation(abscissas,ordinates,targets[,interpolation])
@DESCRIPTION=
interpolation returns interpolated values corresponding
to the given abscissa targets as a one column matrix.
@abscissas are the absicssas of the data to interpolate.
@ordinates are the ordinates of the data to interpolate.
* Strings and empty cells in @abscissas and @ordinates are simply ignored.
@targets are the abscissas of the interpolated data. If several data
are provided, they must be in the same column, in consecutive cells
@interpolation is the method to be used for the interpolation;
possible values are:
- 0: linear;
- 1: linear with averaging;
- 2: staircase;
- 3: staircase with averaging;
- 4: natural cubic spline;
- 5: natural cubic spline with averaging.
If an averaging method is used, the number of returned values
is one less than the number of targets since the evaluation is made by
averaging the interpolation over the interval between two consecutive data;
in that case, the targets values must be given in increasing order.
