gw@sickkids.UUCP (CFI/Graham Wilson ) (07/30/87)
Wanted: i) Code for Smooth Splines
ii) Code for Axes Generation
Hello.
I am looking for algorithms and/or code for producing smooth cubic splines.
The problem is defined as follows:
Given a series of (non-uniformly spaced) data points <Xi,Yi> (i=0...n) and
error values <dYi> (i = 0...n) along with a smoothing factor S >= 0, I need
an algorithm to produce a smooth spline g() such that for each i=0...n, it
holds that
|g(Xi) - Yi| <= S*dYi
(i.e., S*dYi is the maximum that the curve can deviate from Yi - hence if
S == 0 or dYi == 0 for i=0...n, then a natural cubic spline is generated).
Smooth splines are used for weeding out outlier points. I need them to
produce sigmodial curves (no max or min, max one point of inflection).
I have some old fortran code which seems to work for uniformly-spaced data,
but produces roller-coasters for non-uniformly spaces data.
I am also looking for algorithms and/or code to generated axes where
the axes are either linear/linear, linear/log, log/linear, or log/log.
Great thanks in advance.
Graham Wilson | ...allegra ...decvax
CyberFluor Inc | \ \
179 John St., Suite 400 | ...linus!utcrsi!utzoo!sickkids!cfi!graham
Toronto, Ontario, M5T 4B1 | / /
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