message: Core: Fix in Hamiltonian_Heisenberg::FFT_spins(...)
  mu_s was taken at the index of the basis atom and not of the spin
diff: @@ -1090,9 +1090,9 @@ namespace Engine
  int idx_orig = bi + B * (a + Na * (b + Nb * c));
  int idx = bi * spin_stride.basis + a * spin_stride.a + b * spin_stride.b + c * spin_stride.c;
  - fft_spin_inputs[idx ] = spins[idx_orig][0] * geometry->mu_s[bi];
  - fft_spin_inputs[idx + 1 * spin_stride.comp ] = spins[idx_orig][1] * geometry->mu_s[bi];
  - fft_spin_inputs[idx + 2 * spin_stride.comp ] = spins[idx_orig][2] * geometry->mu_s[bi];
  + fft_spin_inputs[idx ] = spins[idx_orig][0] * geometry->mu_s[idx_orig];
  + fft_spin_inputs[idx + 1 * spin_stride.comp ] = spins[idx_orig][1] * geometry->mu_s[idx_orig];
  + fft_spin_inputs[idx + 2 * spin_stride.comp ] = spins[idx_orig][2] * geometry->mu_s[idx_orig];
  }
  }
  }
  