A few functions are also provided in order to perform simple Gaussian quadrature over a fixed interval. The first is gauss_quad which performs fixed-order Gaussian quadrature. The second function is gauss_quadtol which performs Gaussian quadrature of multiple orders until the difference in the integral estimate is beneath some tolerance supplied by the user. These functions both use the module integrate.orthogonal which can calculate the roots and quadrature weights of a large variety of orthogonal polynomials.