runge, a C++ code which evaluates the Runge() function, its first and second derivatives, and its antiderivative. This function causes a breakdown for polynomial interpolation over equally spaced nodes in [-1,+1].
The information on this web page is distributed under the MIT license.
runge is available in a C version and a C++ version and a Fortran77 version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
humps, a C++ code which evaluates the humps() function, its first and second derivatives, and its antiderivative. The functions are plotted using gnuplot().
sigmoid, a C++ code which evaluates the sigmoid function s(x)=1/(1+exp(-x)) or its derivatives of any order. The test code creates graphic images using gnuplot().