Interpolation 24.0.9

This is another rebased PR for integrating interpolated accesses.

Iterpolation accesses work like absolute_access except they can be savely applied on all fields (i.e. with boundary checks).

More info here: !20 (closed)

This PR contains some dead code that uses https://github.com/theHamsta/CubicInterpolationCUDA . I have not included it as a submodule in pystencils in this PR.

This PR break the hash of those two test:

[gw11] [ 14%] FAILED lbmpy_tests/test_code_hashequivalence.py::test_hash_equivalence_llvm 
lbmpy_tests/test_conserved_quantity_relaxation_invariance.py::test_srt 
[gw8] [ 15%] FAILED lbmpy_tests/test_code_hashequivalence.py::test_hash_equivalence 

pystencils/backends/cbackend.py

@@ -103,6 +103,10 @@ def get_headers(ast_node: Node) -> Set[str]:
         if isinstance(a, Node):
             headers.update(get_headers(a))
 
+    for g in get_global_declarations(ast_node):
+        if isinstance(g, Node):
+            headers.update(get_headers(g))
+
     return sorted(headers)
 
 
@@ -132,6 +136,12 @@ class CustomCodeNode(Node):
     def undefined_symbols(self):
         return self._symbols_read - self._symbols_defined
 
+    def __eq___(self, other):
+        return self._code == other._code
+
+    def __hash__(self):
+        return hash(self._code)
+
 
 class PrintNode(CustomCodeNode):
     # noinspection SpellCheckingInspection
@@ -264,6 +274,12 @@ class CBackend:
     def _print_CustomCodeNode(self, node):
         return node.get_code(self._dialect, self._vector_instruction_set)
 
+    def _print_SourceCodeComment(self, node):
+        return "/* " + node.text + " */"
+
+    def _print_EmptyLine(self, node):
+        return ""
+
     def _print_Conditional(self, node):
         cond_type = get_type_of_expression(node.condition_expr)
         if isinstance(cond_type, VectorType):
@@ -428,6 +444,7 @@ class CustomSympyPrinter(CCodePrinter):
             condition=self._print(var) + ' <= ' + self._print(end)  # if start < end else '>='
         )
         return code
+
     _print_Max = C89CodePrinter._print_Max
     _print_Min = C89CodePrinter._print_Min