Add DiscreteFunctionP0::fill utility

src/scheme/DiscreteFunctionP0.hpp

@@ -50,6 +50,14 @@ class DiscreteFunctionP0 : public IDiscreteFunction
     return m_discrete_function_descriptor;
   }
 
+  PUGS_INLINE
+  void
+  fill(const DataType& data) const noexcept
+  {
+    static_assert(not std::is_const_v<DataType>, "Cannot modify ItemValue of const");
+    m_cell_values.fill(data);
+  }
+
   PUGS_FORCEINLINE
   DataType&
   operator[](const CellId cell_id) const noexcept(NO_ASSERT)