Problem header file definitions.hpp

The problem header file definitions.hpp contains major parameters which strongly affect the code structure. For this reason, they require re-compilation. A particular effort has been made to limit their number to a minimum. Each option is a C preprocessor directive. The available options are listed below

COMPONENTS

Sets the number of vector components to the system (for the velocity and magnetic field). Valid options are 1, 2 or 3.

DIMENSIONS

Sets the number of dimensions of the physical system. Note that DIMENSIONS<=COMPONENTS. It is therefore possible to have more COMPONENTS than DIMENSIONS (as is the case for axisymmetric systems which have COMPONENTS=3 and DIMENSIONS=2).

GEOMETRY

Sets the global geometry of the coordinate system used by the code. Note that the coordinates used by Idefix \((x_1, x_2, x_3)\) are fully generic. It is the geometry which translates these generic coordinates into physical coordinates

The available options are:

• CARTESIAN: a cartesian frame \((x_1,x_2,x_3)=(x,y,z)\)

• CYLINDRICAL: cylindrical frame, which should be used only in conjonction with DIMENSIONS=2 (2D axisymmetric setup): \((x_1,x_2,x_3)=(R,z,\phi)\). Note that because the frame is right handed, \(\phi\) is reversed compared to its usual defitinition.

• POLAR: a polar frame: \((x_1,x_2,x_3)=(R,\phi,z)\). This geometry should be used when doing 3D cylindrical problems.

• SPHERICAL: spherical frame \((x_1,x_2,x_3)=(R,\theta,\phi)\) which can be used in 1D, 2D or 3D.

ISOTHERMAL

If ISOTHERMAL is defined, then the code does not solve the energy equation and instead assume a globally isothermal flow. Otherwise, the flow is assumed to be adiabatic.