diff --git a/math/spline_2d.py b/math/spline_2d.py index 21dbc4e..2ae95c1 100644 --- a/math/spline_2d.py +++ b/math/spline_2d.py @@ -9,16 +9,26 @@ import numpy import scipy.interpolate class spline_2d: - """Simple interpolation for two-dimensional curve. - Created to handle the quirks of current SciPy interpolation - routines.""" + """Simple interpolation or smooth approximation + of a two-dimensional curve. + + Input parameters: + + - s: smoothing of the spline curve. The default is 0, + which means plain interpolation, no no extra smoothing. + If s > 0, then some smoothing is performed, and the + curve represents an approximation of the input x,y + curve. + - w: the weight factor for each data point. + """ # Important notes on spline CAVEATS: - # - for some reason we HAVE to make a copy of the 'x' array - # (to make it contiguous, probably?) - # - also, the x values better be sorted in ascending order, or else + # - the x values better be sorted in ascending order, or else # the routine would return nonsense (i.e. NaN's). - def __init__(self, x, y): + # - no two same values of x can be specified. + def __init__(self, x, y, w=None, s=0): self.init(x,y) + self.s = s + self.w = w def init(self, x, y): # First, the x must be sorted, so we make a private copy of @@ -29,7 +39,7 @@ class spline_2d: self.x = self.data['x'] self.y = self.data['y'] # Quirk 2: the x data for spline function must be contiguous - # See below in init_spline_params() + # (No, now this is handled by splrep() properly.) #self.x_copy = self.x.copy() try: @@ -43,7 +53,7 @@ class spline_2d: calling the first spline function if you want different, non-default parameters.""" self.spline_params \ - = scipy.interpolate.splrep(self.x, self.y, s=0) + = scipy.interpolate.splrep(self.x, self.y, w=self.w, s=self.s) def spline(self, xnew): try: