Partial differential equations (PDE) on manifolds arise in many areas,
including mathematics and many applied fields. Due to the complicated geometrical structure of the manifold, it is
difficult to get efficient numerical method to solve PDE on manifold. In the paper,
we propose a method called point integral method (PIM) to solve the Poisson-type
equations from point clouds. Among different kinds of PDEs,
the Poisson-type equations including the standard Poisson equation and
the related eigenproblem of the Laplace-Beltrami operator are one
of the most important. In PIM, the key idea
is to derive the integral equations which approximates the Poisson-type equations
and contains no derivatives but only the values of the unknown function.
This feature makes the integral equation easy to be discretized from point cloud.
In the paper, we explain the derivation of the integral equations, describe the point
integral method and its implementation, and present the numerical experiments
to demonstrate the convergence of PIM.