  We present an update of the General-relativistic multigrid numerical (Gmunu)
code, a parallelized, multi-dimensional curvilinear, general relativistic
magnetohydrodynamics code with an efficient non-linear cell-centred multigrid
(CCMG) elliptic solver, which is fully coupled with an efficient block-based
adaptive mesh refinement modules. Currently, Gmunu is able to solve the
elliptic metric equations in the conformally flat condition (CFC) approximation
with the multigrid approach and the equations of ideal general-relativistic
magnetohydrodynamics by means of high-resolution shock-capturing finite volume
method with reference-metric formularise multi-dimensionally in cartesian,
cylindrical or spherical geometries. To guarantee the absence of magnetic
monopoles during the evolution, we have developed an elliptical divergence
cleaning method by using multigrid solver. In this paper, we present the
methodology, full evolution equations and implementation details of our code
Gmunu and its properties and performance in some benchmarking and challenging
relativistic magnetohydrodynamics problems.

Instrumentation and Methods for Astrophysics;High Energy Astrophysical Phenomena;General Relativity and Quantum Cosmology