Estimate the slope of an interpolating function using a parabola
Returns estimates of the slope of an interpolating function that runs through a set of points in the xy-plane.
parabolaSlopes(x,y)
x,y |
coordinates of points defining the interpolating function. |
Returns an estimate of the slope of the interpolant at (x,y).
This function is used as part of the Stineman
interpolation function stinterp.
It is rarely called directly by the user,
and checking of x and y must be performed by the calling function.
The parabola method provides a better approximation of the slope for smooth functions
than the original method suggested by Stineman (1980), which is provided by
the function stinemanSlopes (see the documentation
of the function stinterp for further information),
but it results in higher slopes near abrupt steps or spikes
and can lead to some overshooting where Stineman's method does not.
Norbert Nemec, Institute of Theoretical Physics, University of Regensburg. Translation from Python code by Halldor Bjornsson
stinterp and stinemanSlopes.
x <- seq(0,2*pi,by=pi/6) y <- sin(x) ## Not run: parabolaSlopes(x,y)
Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.