Welcome to gcvspline's documentation!


gcvspline is a small Python package wrapping the gcvspl.f FORTRAN library, created by H.J. Woltring and available on the netlib.

Code available at https://github.com/charlesll/gcvspline


pip install . or to get the latest tagged version:

pip install gcvspline


conda install -c charlesll gcvspline=0.4

Note that the conda install only works for linux 64 at this time

Licence information

The gcvspline python wrapper is provided under a GNU GPL3 licence, however please take into account the Licence header in gcvspl.f for full licence information:

From the header of gcvspl.f:

"(C) COPYRIGHT 1985, 1986: H.J. Woltring This software is copyrighted, and may be copied for exercise, study and use without authorization from the copyright owner(s), in compliance with paragraph 16b of the Dutch Copyright Act of 1912 ("Auteurswet 1912"). Within the constraints of this legislation, all forms of academic and research-oriented excercise, study, and use are allowed, including any necessary modifications. Copying and use as object for commercial exploitation are not allowed without permission of the copyright owners, including those upon whose work the package is based."


gcvspline is provided as is, use at your own risks.

Available functions

Functions are documented and a call with help() of pydoc will provide all the relevant informations.

  • gcvspline and splderivative that are direct wrappers of the FORTRAN functions. See gcvspline_fortran_interface.py for an example.

  • Scipy-like interface of several functions: GCVSmoothedNSpline, MSESmoothedNSpline, DOFSmoothedNSpline, SmoothedNSpline. See ./examples/gcvspline_scipylike_interface.ipynb for examples.


Examples are available in the example folder of gcvspline.

A short example is the fitting of a spline to noisy data:

from gcvspline import GCVSmoothedNSpline

x = np.linspace(-3, 3, 50)
y0 = np.exp(-x**2)

n = 0.1 * np.random.normal(size=50)
w = 1.0 / (np.ones_like(n) * std(n))
y = y0 + n

xs = np.linspace(-3, 3, 1000)

GCV_auto = GCVSmoothedNSpline(x, y, w=w) # gcvspline fit

y_smoothed = GCV_auto(xs) # retrieving the smoothed values


Charles Le Losq, the Australian National University (RSES), Canberra.

Yu Feng, University of California, Berkeley.

contact: charles.lelosq@anu.edu.au or yfeng1@berkeley.edu



Woltring, 1986, A FORTRAN package for generalized, cross-validatory spline smoothing and differentiation. Adv. Eng. Softw. 8:104-113.

and references cited therein.

gcvspl.f code available on www.netlib.org, other versions are available on https://isbweb.org/software/sigproc.html The gcvspl.f code shipped in this package is a Fortran 77 version downloaded on https://isbweb.org/software/sigproc.html