hydrogen-radial: computes the arbitrary precision closed-form formula for the radial wavefunction of hydrogen atom.spherical-harmonics: computes the arbitrary precision closed-form formula for the spherical harmonics.render-hydrogen: renders hydrogen electron probability density with arbitrary precision computation.spherical-bessel: computes the arbitrary precision closed-form formula for the spherical bessel functions.resonance-scattering: plots the resonance scattering for the partial waves of constant spherical well potential, this reproduces Figure 6.15, and allows to plot with different parameter values.kohn-sham: carries out the detailed calculation of helium atom ground state based on the recipe given by the density function theory, and kohn-sham equation. This fills all the gaps left in section 7.6.5 and reproduces table 7.1 and figure 7.1