/** propagate angular velocities and quaternions \todo implement for
fixed_coord_flag */
void propagate_omega_quat_particle(Particle* p)
{
double lambda;
double Qd[4], Qdd[4], S[3], Wd[3];
#ifdef ROTATION_PER_PARTICLE
if (!p->p.rotation) return;
#endif
define_Qdd(p, Qd, Qdd, S, Wd);
lambda = 1 - S[0]*time_step_squared_half - sqrt(1 - time_step_squared*(S[0] + time_step*(S[1] + time_step_half/2.*(S[2]-S[0]*S[0]))));
for(int j=0; j < 3; j++){
p->m.omega[j]+= time_step_half*Wd[j];
}
ONEPART_TRACE(if(p->p.identity==check_id) fprintf(stderr,"%d: OPT: PV_1 v_new = (%.3e,%.3e,%.3e)\n",this_node,p->m.v[0],p->m.v[1],p->m.v[2]));
p->r.quat[0]+= time_step*(Qd[0] + time_step_half*Qdd[0]) - lambda*p->r.quat[0];
p->r.quat[1]+= time_step*(Qd[1] + time_step_half*Qdd[1]) - lambda*p->r.quat[1];
p->r.quat[2]+= time_step*(Qd[2] + time_step_half*Qdd[2]) - lambda*p->r.quat[2];
p->r.quat[3]+= time_step*(Qd[3] + time_step_half*Qdd[3]) - lambda*p->r.quat[3];
// Update the director
convert_quat_to_quatu(p->r.quat, p->r.quatu);
#ifdef DIPOLES
// When dipoles are enabled, update dipole moment
convert_quatu_to_dip(p->r.quatu, p->p.dipm, p->r.dip);
#endif
ONEPART_TRACE(if(p->p.identity==check_id) fprintf(stderr,"%d: OPT: PPOS p = (%.3f,%.3f,%.3f)\n",this_node,p->r.p[0],p->r.p[1],p->r.p[2]));
}
/** propagate angular velocities and quaternions \todo implement for
fixed_coord_flag */
void propagate_omega_quat()
{
Particle *p;
Cell *cell;
int c,i,j, np;
double lambda, dt2, dt4, dtdt, dtdt2;
dt2 = time_step*0.5;
dt4 = time_step*0.25;
dtdt = time_step*time_step;
dtdt2 = dtdt*0.5;
INTEG_TRACE(fprintf(stderr,"%d: propagate_omega_quat:\n",this_node));
for (c = 0; c < local_cells.n; c++) {
cell = local_cells.cell[c];
p = cell->part;
np = cell->n;
for(i = 0; i < np; i++) {
double Qd[4], Qdd[4], S[3], Wd[3];
#ifdef VIRTUAL_SITES
// Virtual sites are not propagated in the integration step
if (ifParticleIsVirtual(&p[i]))
continue;
#endif
define_Qdd(&p[i], Qd, Qdd, S, Wd);
lambda = 1 - S[0]*dtdt2 - sqrt(1 - dtdt*(S[0] + time_step*(S[1] + dt4*(S[2]-S[0]*S[0]))));
for(j=0; j < 3; j++){
p[i].m.omega[j]+= dt2*Wd[j];
}
ONEPART_TRACE(if(p[i].p.identity==check_id) fprintf(stderr,"%d: OPT: PV_1 v_new = (%.3e,%.3e,%.3e)\n",this_node,p[i].m.v[0],p[i].m.v[1],p[i].m.v[2]));
p[i].r.quat[0]+= time_step*(Qd[0] + dt2*Qdd[0]) - lambda*p[i].r.quat[0];
p[i].r.quat[1]+= time_step*(Qd[1] + dt2*Qdd[1]) - lambda*p[i].r.quat[1];
p[i].r.quat[2]+= time_step*(Qd[2] + dt2*Qdd[2]) - lambda*p[i].r.quat[2];
p[i].r.quat[3]+= time_step*(Qd[3] + dt2*Qdd[3]) - lambda*p[i].r.quat[3];
// Update the director
convert_quat_to_quatu(p[i].r.quat, p[i].r.quatu);
#ifdef DIPOLES
// When dipoles are enabled, update dipole moment
convert_quatu_to_dip(p[i].r.quatu, p[i].p.dipm, p[i].r.dip);
#endif
ONEPART_TRACE(if(p[i].p.identity==check_id) fprintf(stderr,"%d: OPT: PPOS p = (%.3f,%.3f,%.3f)\n",this_node,p[i].r.p[0],p[i].r.p[1],p[i].r.p[2]));
}
}
}
/** Rotate the particle p around the NORMALIZED axis aSpaceFrame by amount phi */
void rotate_particle(Particle* p, double* aSpaceFrame, double phi)
{
// Convert rotation axis to body-fixed frame
double a[3];
convert_vec_space_to_body(p,aSpaceFrame,a);
// Apply restrictions from the rotation_per_particle feature
#ifdef ROTATION_PER_PARTICLE
// printf("%g %g %g - ",a[0],a[1],a[2]);
// Rotation turned off entirely?
if (p->p.rotation <2) return;
// Per coordinate fixing
if (!(p->p.rotation & 2)) a[0]=0;
if (!(p->p.rotation & 4)) a[1]=0;
if (!(p->p.rotation & 8)) a[2]=0;
// Re-normalize rotation axis
double l=sqrt(sqrlen(a));
// Check, if the rotation axis is nonzero
if (l<1E-10) return;
for (int i=0;i<3;i++)
a[i]/=l;
// printf("%g %g %g\n",a[0],a[1],a[2]);
#endif
double q[4];
q[0]=cos(phi/2);
double tmp=sin(phi/2);
q[1]=tmp*a[0];
q[2]=tmp*a[1];
q[3]=tmp*a[2];
// Normalize
normalize_quaternion(q);
// Rotate the particle
double qn[4]; // Resulting quaternion
multiply_quaternions(p->r.quat,q,qn);
for (int k=0; k<4; k++)
p->r.quat[k]=qn[k];
convert_quat_to_quatu(p->r.quat, p->r.quatu);
#ifdef DIPOLES
// When dipoles are enabled, update dipole moment
convert_quatu_to_dip(p->r.quatu, p->p.dipm, p->r.dip);
#endif
}
