call Grid_dfsvBeginSystem( integer(IN), dimension(VARDESC_SIZE) :: baseVarDesc, integer(IN) :: ntotVars, OPTIONAL,integer(IN) :: pass)
This routine advances a generalized diffusion operator of the form A*(df/dt) + C*f = div(B*grad(f)) + D , where f = f(x,t) is the Variable to be diffused (x=1D..3D position); Presently it is used to do heat conduction and multigroup diffusion.
baseVarDesc : A variable on which the diffusion operation is performed, usually an extra variable, used to identify the system ntotVars : total number or variables to solve for / equations to solve
This implementation * supports: 1D, 2D PARAMESH (with local refinement) 1D, 2D, 3D in UG (3D untested). 1D Spherical in PARAMESH/UG 1D, 2D Cylindrical in PARAMESH/UG (R-Z) * uses HYPRE library to solve AX = B