Mesh::Hex8::FineLayer port convenience functions

[tdegeus]

Port convenience functions from Mesh::Quad4::FineLayer

GooseFEM/include/GooseFEM/MeshQuad4.h

Lines 102 to 195 in a31c545

	/**
	Reconstruct class for given coordinates / connectivity.
	\tparam C e.g. `xt::xtensor<double, 2>`
	\tparam E e.g. `xt::xtensor<size_t, 2>`
	\param coor Nodal coordinates ``[nnode, ndim]`` with ``ndim == 2``.
	\param conn Connectivity ``[nne, nne]`` with ``nne == 4``.
	\throw GOOSEFEM_CHECK()
	*/
	template <class C, class E, std::enable_if_t<xt::is_xexpression<C>::value, bool> = true>
	FineLayer(const C& coor, const E& conn);
	/**
	Edge size in x-direction of a block, in units of #h, per row of blocks.
	Note that a block is equal to an element except in refinement layers
	where it contains three elements.
	\return List of size equal to the number of rows of blocks.
	*/
	xt::xtensor<size_t, 1> elemrow_nhx() const;
	/**
	Edge size in y-direction of a block, in units of #h, per row of blocks.
	Note that a block is equal to an element except in refinement layers
	where it contains three elements.
	\return List of size equal to the number of rows of blocks.
	*/
	xt::xtensor<size_t, 1> elemrow_nhy() const;
	/**
	Number of elements per row of blocks.
	Note that a block is equal to an element except in refinement layers
	where it contains three elements.
	\return List of size equal to the number of rows of blocks.
	*/
	xt::xtensor<size_t, 1> elemrow_nelem() const;
	/**
	Elements in the middle (fine) layer.
	\return List of element numbers.
	*/
	xt::xtensor<size_t, 1> elementsMiddleLayer() const;
	/**
	Elements along a layer.
	\return List of element numbers.
	*/
	xt::xtensor<size_t, 1> elementsLayer(size_t layer) const;
	/**
	Select region of elements from 'matrix' of element numbers.
	\return List of element numbers.
	*/
	xt::xtensor<size_t, 1> elementgrid_ravel(
	std::vector<size_t> rows_start_stop,
	std::vector<size_t> cols_start_stop) const;
	/**
	Select region of elements from 'matrix' of element numbers around an element:
	square box with edge-size ``(2 * size + 1) * h``, around ``element``.
	\param element The element around which to select elements.
	\param size Edge size of the square box encapsulating the selected element.
	\param periodic Assume the mesh periodic.
	\return List of elements.
	*/
	xt::xtensor<size_t, 1>
	elementgrid_around_ravel(size_t element, size_t size, bool periodic = true);
	/**
	Select region of elements from 'matrix' of element numbers around an element:
	left/right from ``element`` (on the same layer).
	\param element The element around which to select elements.
	\param left Number of elements to select to the left.
	\param right Number of elements to select to the right.
	\param periodic Assume the mesh periodic.
	\return List of elements.
	*/
	// -
	xt::xtensor<size_t, 1>
	elementgrid_leftright(size_t element, size_t left, size_t right, bool periodic = true);
	/**
	Mapping to 'roll' periodically in the x-direction,
	\return element mapping, such that: new_elemvar = elemvar[elem_map]
	*/
	xt::xtensor<size_t, 1> roll(size_t n);

see also #238