Basic shapes are fundamendal PDFs, with often well-known functional form. They are usually fully analytically implemented and often a thin wrapper around Distribution. Any missing shape can be easily wrapped using WrapDistribution.

 zfit.pdf.Gauss(mu, sigma, obs, *[, ...]) Gaussian or Normal distribution with a mean (mu) and a standartdeviation (sigma). zfit.pdf.Exponential([lam, obs, extended, ...]) Exponential function exp(lambda * x). zfit.pdf.CrystalBall(mu, sigma, alpha, n, obs, *) Crystal Ball shaped PDF. zfit.pdf.DoubleCB(mu, sigma, alphal, nl, ...) Double-sided Crystal Ball shaped PDF. zfit.pdf.GeneralizedCB(mu, sigmal, alphal, ...) Generalized asymmetric double-sided Crystal Ball shaped PDF. zfit.pdf.GaussExpTail(mu, sigma, alpha, obs, *) GaussExpTail shaped PDF. zfit.pdf.GeneralizedGaussExpTail(mu, sigmal, ...) GeneralizedGaussedExpTail shaped PDF which is Generalized assymetric double-sided GaussExpTail shaped PDF. zfit.pdf.Uniform(low, high, obs, *[, ...]) Uniform distribution which is constant between low, high and zero outside. zfit.pdf.Cauchy(m, gamma, obs, *[, ...]) Non-relativistic Breit-Wigner (Cauchy) PDF representing the energy distribution of a decaying particle. zfit.pdf.Voigt(m, sigma, gamma[, obs, ...]) Voigt profile. zfit.pdf.TruncatedGauss(mu, sigma, low, ...) Gaussian distribution that is 0 outside of low, high. zfit.pdf.BifurGauss(mu, sigmal, sigmar, obs, *) Bifurcated Gaussian distribution different standard deviations for the left and right side of the mean. zfit.pdf.Poisson([lam, obs, extended, norm, ...]) Poisson distribution, parametrized with an event rate parameter (lamb). zfit.pdf.LogNormal(mu, sigma, obs, *[, ...]) Log-normal distribution, the exponential of a normal distribution. zfit.pdf.QGauss(q, mu, sigma, obs, *[, ...]) Q-Gaussian distribution with parameter q. zfit.pdf.ChiSquared(ndof, obs, *[, ...]) ChiSquared distribution for ndof degrees of freedom. zfit.pdf.StudentT(ndof, mu, sigma, obs[, ...]) StudentT distribution for ndof degrees of freedom. zfit.pdf.Gamma(gamma, beta, mu, obs, *[, ...]) Gamma distribution. zfit.pdf.JohnsonSU(mu, lambd, gamma, delta, ...) Johnson's SU distribution.