CalculateEntropy_MultiSetModel3D_t Subroutine

  subroutine CalculateEntropy_MultiSetModel3D_t(this)
    !! entropy = sum over sets k of the entropy of set k. Each set's CalculateEntropy is
    !! collective over its communicator, so it runs on every set, empty or not.
    implicit none
    class(MultiSetModel3D_t),intent(inout) :: this
    ! Local
    integer :: k

    this%entropy = 0.0_prec
    do k = 1,this%nSets
      call this%sets(k)%model%CalculateEntropy()
      this%entropy = this%entropy+this%sets(k)%model%entropy
    enddo

  endsubroutine CalculateEntropy_MultiSetModel3D_t