Add isDefaultMaterial() method to Material class

Redmine: #1871

Core/Material/Material.cpp

@@ -69,6 +69,11 @@ complex_t Material::materialData() const
     return m_material_impl->materialData();
 }
 
+bool Material::isDefaultMaterial() const
+{
+    return materialData() == complex_t() && isScalarMaterial();
+}
+
 complex_t Material::scalarSubtrSLD(const WavevectorInfo& wavevectors) const
 {
     return m_material_impl->scalarSubtrSLD(wavevectors);

Core/Material/Material.h

@@ -81,6 +81,10 @@ public:
     //! Returns true if material underlying data is nullptr
     bool isEmpty() const {return !m_material_impl;}
 
+    //! Returns true if material has refractive index of (1.0, 0.0)
+    //! and zero magnetization.
+    bool isDefaultMaterial() const;
+
     //! Returns (\f$ \pi/\lambda^2 \f$ - sld), sld (in \f$nm^{-2}\f$) being the scattering length density
     complex_t scalarSubtrSLD(const WavevectorInfo& wavevectors) const;