  We present for astrophysical use a multi-dimensional numerical code to solve
the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit
finite difference method on an Eulerian grid, called the Total Variation
Diminishing (TVD) scheme, which is a second-order-accurate extension of the
Roe-type upwind scheme. Multiple spatial dimensions are treated through a
Strang-type operator splitting. The constraint of a divergence-free field is
enforced exactly by calculating a correction via a gauge transformation in each
time step.
  Results from two-dimensional shock tube tests show that the code captures
correctly discontinuities in all three MHD waves families as well as contact
discontinuities. The numerical viscosities and resistivity in the code, which
are useful in order to understand simulations involving turbulent flows, are
estimated through the decay of two-dimensional linear waves. Finally, the
robustness of the code in two-dimensions is demonstrated through calculations
of the Kelvin-Helmholtz instability and the Orszag-Tang vortex.
