sigmoid, a C code which evaluates the sigmoid function s(x)=1/(1+exp(-x)) or a derivative of any order. The test code creates graphic images using gnuplot().
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sigmoid 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.
gnuplot_test, a C code which writes data and command files so that gnuplot() plots the results.
humps, a C code which evaluates the humps() function, its first and second derivatives, and its antiderivative. The functions are plotted using gnuplot().
polpak, a C code which evaluates a variety of mathematical functions, polynomials, and sequences, including Bell, Benford, Bernoulli, Bernstein, Cardan, Catalan, Charlier, Chebyshev, Collatz, Delannoy, Euler, Fibonacci, Gegenbauer, Gudermannian, Harmonic, Hermite, Hofstadter, Hypergeometric 2F1, Jacobi, Krawtchouk, Laguerre, Lambert W, Legendre, Lerch, Meixner, Mertens, Moebius, Motzkin, Phi, Stirling Numbers, Tau, Tribonacci, Zernike.
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 functions are plotted using gnuplot().
sinc, a C code which evaluates the sinc() function, its first and second derivative and its antiderivative. The normalized function is defined by sincn=sin(pi*x)/(pi*x), the unnormalized function is sincu=sin(x)/x. Plots of these functions are made.