Symmetric Gauss Legendre Quadrature Rules for Numerical Integration over an Arbitrary Linear Tetrahedra in Euclidean Three-Dimensional Space

In this paper it is proposed to compute the volume integral of certain functions whose antiderivates with respect to one of the variates (say either x or y or z) is available. Then by use of the well known Gauss Divergence theorem, it can be shown that the volume integral of such a function is expressible as sum of four integrals over the unit triangle. The present method can also evaluate the triple integrals of trivariate polynomials over an arbitrary tetrahedron as a special case. It is also demonstrated that certain integrals which are nonpolynomial functions of trivariates x, y, z can be computed by the proposed method. Then we have applied the symmetric Gauss Legendre quadrature rules to evaluate the typical integrals governed by the proposed method. Mathematics Subject Classification: 65D32