Fix logic and uses ranges in interpolate (#4049)

* Add failing test

* Add fix that compares the underlying mesh before using copy without dof transformation

* Swith order of comparsions to do pointers first.

* Further clarifications in the interpolation code for matching meshes

* Remove unused variable

* Add test checking that copying only happens when cells0 is equal to arange(num_cells_local+num_ghosts)

* Doc linting

* Another doc linting fix

* Clang formatting

* Use size_t

* Simplify

* Simplifications

* const fixes

* Add debug check

* Fix

* Simplify

* Fix typo

* Small doc improvements

* Use ranges

* More ranges

* More ranges

* Updates

* Doc fixes

* Logic fix

* Simplify

* Small fix

* Tidy up

* Use new interface

* Binding fix

* Simplify

* Improvements

* Fix

* More logix improvements

* Update Expression logic

* Simplify

* Re-enable test

* Simplification

* Remove commented code

* Iterator improvements

* Tidy

* Update cpp/dolfinx/fem/Function.h

Co-authored-by: Paul T. Kühner <56360279+schnellerhase@users.noreply.github.com>

* Add sign test

* Name updates

* Update cpp/dolfinx/fem/interpolate.h

Co-authored-by: Paul T. Kühner <56360279+schnellerhase@users.noreply.github.com>

* Tidy

* Tidy

* Code improvements

* Remove testing

* Tidy docs

* Doc improvements

* Small upate

* Small update

---------

Co-authored-by: jorgensd <dokken92@gmail.com>
Co-authored-by: Jørgen S. Dokken <dokken@simula.no>
Co-authored-by: Paul T. Kühner <56360279+schnellerhase@users.noreply.github.com>

Author: 3 people

cpp/demo/custom_kernel/main.cpp

@@ -83,7 +83,7 @@ double assemble_matrix0(std::shared_ptr<const fem::FunctionSpace<T>> V,
   auto sp = la::SparsityPattern(
       V->mesh()->comm(), {dofmap->index_map, dofmap->index_map},
       {dofmap->index_map_bs(), dofmap->index_map_bs()});
-  fem::sparsitybuild::cells(sp, {cells, cells}, {*dofmap, *dofmap});
+  fem::sparsitybuild::cells(sp, std::pair{cells, cells}, {*dofmap, *dofmap});
   sp.finalize();
   la::MatrixCSR<T> A(sp);
   common::Timer timer("Assembler0 std::function (matrix)");
@@ -134,7 +134,7 @@ double assemble_matrix1(const mesh::Geometry<T>& g, const fem::DofMap& dofmap,
   auto sp = la::SparsityPattern(dofmap.index_map->comm(),
                                 {dofmap.index_map, dofmap.index_map},
                                 {dofmap.index_map_bs(), dofmap.index_map_bs()});
-  fem::sparsitybuild::cells(sp, {cells, cells}, {dofmap, dofmap});
+  fem::sparsitybuild::cells(sp, std::pair{cells, cells}, {dofmap, dofmap});
   sp.finalize();
   la::MatrixCSR<T> A(sp);
   auto ident = [](auto, auto, auto, auto) {}; // DOF permutation not required

cpp/demo/interpolation_different_meshes/main.cpp

@@ -11,6 +11,7 @@
 #include <dolfinx/io/ADIOS2Writers.h>
 #include <dolfinx/mesh/generation.h>
 #include <memory>
+#include <ranges>
 
 using namespace dolfinx;
 using T = double;
@@ -72,14 +73,13 @@ int main(int argc, char* argv[])
     auto cell_map
         = mesh_hex->topology()->index_map(mesh_hex->topology()->dim());
     assert(cell_map);
-    std::vector<std::int32_t> cells(
-        cell_map->size_local() + cell_map->num_ghosts(), 0);
-    std::iota(cells.begin(), cells.end(), 0);
+    auto cells = std::ranges::views::iota(0, cell_map->size_local()
+                                                 + cell_map->num_ghosts());
     geometry::PointOwnershipData<T> interpolation_data
         = fem::create_interpolation_data(
             u_hex->function_space()->mesh()->geometry(),
             *u_hex->function_space()->element(),
-            *u_tet->function_space()->mesh(), std::span(cells), 1e-8);
+            *u_tet->function_space()->mesh(), cells, 1e-8);
     u_hex->interpolate(*u_tet, cells, interpolation_data);
 
 #ifdef HAS_ADIOS2

cpp/dolfinx/common/types.h

@@ -28,12 +28,14 @@ struct scalar_value
   /// @internal
   typedef T type;
 };
+
 /// @private
 template <scalar T>
 struct scalar_value<T, std::void_t<typename T::value_type>>
 {
   typedef typename T::value_type type;
 };
+
 /// @private Convenience typedef
 template <scalar T>
 using scalar_value_t = typename scalar_value<T>::type;

cpp/dolfinx/fem/ElementDofLayout.cpp

@@ -9,6 +9,7 @@
 #include <cassert>
 #include <functional>
 #include <numeric>
+#include <span>
 #include <stdexcept>
 
 using namespace dolfinx;

cpp/dolfinx/fem/FiniteElement.h

@@ -87,7 +87,7 @@ class FiniteElement
   ///
   /// This constructs a mixed element \f$E_0 \times E_1 \times \ldots
   /// \times E_{n-1}\f$. The *i*th sub-element \f$E_i\f$ can be accessed
-  /// by ::extract_sub_element. Functions defined on mixed element
+  /// by ::extract_sub_element. Function%s defined on mixed element
   /// spaces cannot be interpolated into directly. It is necessary to
   /// first extract a sub-Function (view), which can then be
   /// interpolated into.

cpp/dolfinx/fem/Form.h

@@ -542,7 +542,7 @@ class Form
   /// @brief Coefficient function mesh integration entity indices.
   ///
   /// This method is equivalent to ::domain_arg, but returns mesh entity
-  /// indices for coefficient \link Function Functions. \endlink
+  /// indices for coefficient Function%s.
   ///
   /// @param[in] type Integral type.
   /// @param[in] idx Integral identifier.