forbid external, fronting and z-field

Resample/Slice/Slice.cpp

@@ -82,6 +82,10 @@ SpinMatrix Slice::polarizedReducedPotential(R3 k, double n_ref) const
 
 void Slice::initBField(R3 h_field, double h_z)
 {
+    // Temporary disable setting z-magnetization in all layers (see issue #653)
+    if(m_material.magnetization().z() != 0)
+        throw std::runtime_error("Processing z-magnetization is not implemented yet.");
+
     static constexpr double Magnetic_Permeability = 4e-7 * pi;
     m_B_field = Magnetic_Permeability * (h_field + m_material.magnetization());
     m_B_field.setZ(Magnetic_Permeability * h_z);

Resample/Slice/SliceStack.cpp

@@ -50,6 +50,14 @@ void SliceStack::addNSlices(size_t n, double thickness, const Material& material
 
 SliceStack SliceStack::setBField(const R3& externalField)
 {
+    // Temporary disable setting non-zero magnetization in fronting medium (see issue #653)
+    if(this->at(0).material().magnetization() != R3())
+        throw std::runtime_error("Processing fronting magnetization is not implemented yet.");
+
+    // Temporary disable setting non-zero external field (see issue #653)
+    if(externalField != R3())
+        throw std::runtime_error("Processing external field is not implemented yet.");
+
     if (this->empty())
         return *this;
     const double M_z0 = this->at(0).material().magnetization().z();