Mesh operations
Accessing functions
Function, e.g. the density are given by an array rho(i,spin), where i ranges over the mesh points associated with the given domain (see domain decomposition), representing
rho( ri, spin )
What is mesh_x_global(mesh, ip) ?
mesh_x_global(mesh, ip) returns a FLOAT vector, corresponding to the coordinates of point ip of the global mesh.
function mesh_x_global(mesh, ipg) result(xx)
class(mesh_t), intent(in) :: mesh
integer(int64), intent(in) :: ipg
FLOAT :: xx(1:mesh%box%dim)
FLOAT :: chi(1:mesh%box%dim)
integer :: ix(1:mesh%box%dim)
! no push_sub because function is called too frequently
call mesh_global_index_to_coords(mesh, ipg, ix)
chi = ix * mesh%spacing
xx = mesh%coord_system%to_cartesian(chi)
end function mesh_x_global
Integration
Integration is implemented as a straightforward summation:
do ip = 1, mesh%np
dd = dd + ff(ip)
end do
Differentiation
Taking derivatives is done by finite differences. The points involved in a derivative are defined by the stencil (see below).
Derivatives are discussed in a separate document Derivatives.md.
Note on packed states:
Note on curvilinear meshes:
The mesh::x(:,:) array always contains a regular mesh, which gets ‘distorded’ to a curvilinear mesh by additional function calls.