Evaluate the function pointers of the dependent variables, and then calculate the difference between these two. ( scalar or vector ) In lua file, first define new variable with varType operation kind as "difference" and provide two dependent variable via input_varname. If input_varname variable is not part of predefined solver variables then add also that variable via variable table for example spacetime function variable. For example: Define a variable called difference, which depend on density and spacetime. one can get an error between simulation results and analytical solution.
\verbatim -- in lua file, one can define as following: variable = {{ name = 'dens_reference', ncomponents = 1, vartype = "st_fun", st_fun = luaFun }, { name = 'dens_difference', ncomponents = 1, vartype = "operation", operation = {kind='difference', input_varname={density, dens_reference}} } ... } tracking = { variable = {'dens_difference'}, folder = 'tracking/', shape = {kind = 'canoND', object = {origin = {3.0,3.1,3.0} } }, format = 'ascii', time = {min = 0, max = tmax, interval = 1}, } \endverbatim
The interface has to comply to the abstract interface tem_varSys_module#tem_varSys_proc_element.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| class(tem_varSys_op_type), | intent(in) | :: | fun |
Description of the method to obtain the variables, here some preset values might be stored, like the space time function to use or the required variables. |
||
| type(tem_varSys_type), | intent(in) | :: | varSys |
The variable system to obtain the variable from. |
||
| integer, | intent(in) | :: | elempos(:) |
Position of the TreeID of the element to get the variable for in the global treeID list. |
||
| type(tem_time_type), | intent(in) | :: | time |
Point in time at which to evaluate the variable. |
||
| type(treelmesh_type), | intent(in) | :: | tree |
global treelm mesh info |
||
| integer, | intent(in) | :: | nElems |
Number of values to obtain for this variable (vectorized access). |
||
| integer, | intent(in) | :: | nDofs |
Number of degrees of freedom within an element. |
||
| real(kind=rk), | intent(out) | :: | res(:) |
Resulting values for the requested variable. Linearized array dimension: (n requested entries) x (nComponents of this variable) x (nDegrees of freedom) Access: (iElem-1)fun%nComponentsnDofs + (iDof-1)*fun%nComponents + iComp |
recursive subroutine evalDiff_forElement( fun, varsys, elempos, time, tree, &
& nElems, nDofs, res )
! ---------------------------------------------------------------------- !
!> Description of the method to obtain the variables, here some preset
!! values might be stored, like the space time function to use or the
!! required variables.
class(tem_varSys_op_type), intent(in) :: fun
!> The variable system to obtain the variable from.
type(tem_varSys_type), intent(in) :: varSys
!> Position of the TreeID of the element to get the variable for in the
!! global treeID list.
integer, intent(in) :: elempos(:)
!> Point in time at which to evaluate the variable.
type(tem_time_type), intent(in) :: time
!> global treelm mesh info
type(treelmesh_type), intent(in) :: tree
!> Number of values to obtain for this variable (vectorized access).
integer, intent(in) :: nElems
!> Number of degrees of freedom within an element.
integer, intent(in) :: nDofs
!> Resulting values for the requested variable.
!!
!! Linearized array dimension:
!! (n requested entries) x (nComponents of this variable)
!! x (nDegrees of freedom)
!! Access: (iElem-1)*fun%nComponents*nDofs +
!! (iDof-1)*fun%nComponents + iComp
real(kind=rk), intent(out) :: res(:)
! ---------------------------------------------------------------------- !
integer :: iDep, posDepVar
! first dimension:nElems,
! second dimension:size of difference variable in input_varname
real(kind=rk), allocatable :: input_varRes(:,:)
! ---------------------------------------------------------------------- !
integer :: nTotal
! ---------------------------------------------------------------------- !
nTotal = nElems*nDofs*fun%nComponents
! nInputs must be two
allocate(input_varRes(nTotal, fun%nInputs))
do iDep = 1, fun%nInputs
! get position of dependent var in varSys
posDepVar = fun%input_varPos(iDep)
! derive dependent variable
call varSys%method%val(posDepVar)%get_element( &
& varSys = varSys, &
& elemPos = elemPos, &
& time = time, &
& tree = tree, &
& nElems = nElems, &
& nDofs = nDofs, &
& res = input_varRes(:, iDep) )
end do
res(:nTotal) = input_varRes(:, 1) - input_varRes(:, 2)
deallocate(input_varRes)
end subroutine evalDiff_forElement