CalculateEntropy_advection_diffusion_3d Subroutine

  subroutine CalculateEntropy_advection_diffusion_3d(this)
    implicit none
    class(advection_diffusion_3d),intent(inout) :: this
    ! Local
    integer :: iel,i,j,k,ivar,ierror
    real(prec) :: e,s,jac

    call gpuCheck(hipMemcpy(c_loc(this%solution%interior), &
                            this%solution%interior_gpu,sizeof(this%solution%interior), &
                            hipMemcpyDeviceToHost))

    e = 0.0_prec
    do ivar = 1,this%solution%nvar
      do iel = 1,this%geometry%nelem
        do k = 1,this%solution%interp%N+1
          do j = 1,this%solution%interp%N+1
            do i = 1,this%solution%interp%N+1
              jac = this%geometry%J%interior(i,j,k,iel,1)
              s = this%solution%interior(i,j,k,iel,ivar)
              e = e+0.5_prec*s*s*jac
            enddo
          enddo
        enddo
      enddo
    enddo

    if(this%mesh%decomp%mpiEnabled) then
      call mpi_allreduce(e, &
                         this%entropy, &
                         1, &
                         this%mesh%decomp%mpiPrec, &
                         MPI_SUM, &
                         this%mesh%decomp%mpiComm, &
                         iError)
    else
      this%entropy = e
    endif

  endsubroutine CalculateEntropy_advection_diffusion_3d