void fdm_zhangli_cpu( int dim_x, int dim_y, int dim_z, double delta_x, double delta_y, double delta_z, bool do_precess, const Matrix &P, const Matrix &xi, const Matrix &Ms, const Matrix &alpha, const VectorMatrix &j, const VectorMatrix &M, VectorMatrix &dM) { VectorMatrix::const_accessor M_acc(M), j_acc(j); Matrix::ro_accessor Ms_acc(Ms), alpha_acc(alpha), P_acc(P), xi_acc(xi); VectorMatrix::accessor dM_acc(dM); for (int z=0; z<dim_z; ++z) for (int y=0; y<dim_y; ++y) for (int x=0; x<dim_x; ++x) { const int k = z*dim_x*dim_y + y*dim_x + x; const double Ms = Ms_acc.at(k); const double alpha = alpha_acc.at(k); const double P = P_acc.at(k); const double xi = xi_acc.at(k); const Vector3d j = j_acc.get(k); dM_acc.set(k, zhangli_dMdt(x, y, z, dim_x, dim_y, dim_z, delta_x, delta_y, delta_z, do_precess, P, xi, Ms, alpha, j, M_acc)); } }
void fdm_slonchewski( int dim_x, int dim_y, int dim_z, double delta_x, double delta_y, double delta_z, double a_j, const VectorMatrix &p, // spin polarization const Matrix &Ms, const Matrix &alpha, const VectorMatrix &M, VectorMatrix &dM) { // Calculate: // c1*(M x (M x p)) + c2*(M x p) // // c1(theta): damping factor // c2(theta): precession factor // Ms*cos(theta) = M*p Matrix::ro_accessor Ms_acc(Ms), alpha_acc(alpha); VectorMatrix::const_accessor p_acc(p); VectorMatrix::const_accessor M_acc(M); VectorMatrix::accessor dM_acc(dM); const int N = dim_x * dim_y * dim_z; for (int n=0; n<N; ++n) { const double alpha = alpha_acc.at(n); const double Ms = Ms_acc.at(n); const Vector3d p = p_acc.get(n); const Vector3d M = M_acc.get(n); if (p == Vector3d(0.0, 0.0, 0.0)) continue; if (Ms == 0.0) continue; // Calculate precession and damping terms const Vector3d Mxp = cross(M, p); // precession: u=mxp const Vector3d MxMxp = cross(M, Mxp); // damping: t=mxu=mx(mxp) // add both terms to dm/dt in LLGE const double gamma_pr = GYROMAGNETIC_RATIO / (1.0 + alpha*alpha); Vector3d dM_n; dM_n.x = gamma_pr * a_j * (-MxMxp.x/Ms + Mxp.x*alpha); dM_n.y = gamma_pr * a_j * (-MxMxp.y/Ms + Mxp.y*alpha); dM_n.z = gamma_pr * a_j * (-MxMxp.z/Ms + Mxp.z*alpha); dM_acc.set(n, dM_n); } }