adds specific initialization for deformation tensor

cpp/particles/particles_input_random.hpp

@@ -110,6 +110,32 @@ class particles_input_random: public abstract_particles_input<partsize_t, partic
             // generate random particle states
             {
                 TIMEZONE("particles_input_random::generate random numbers");
+                if (state_size == 15)
+                    // deformation tensor
+                {
+                    for (partsize_t idx=0; idx < partsize_t(load_splitter.getMySize()); idx++)
+                    {
+                        // positions are uniformly distributed within cube
+                        for (int cc=0; cc < 3; cc++)
+                            split_particle_state[idx*state_size + cc] = udist(rgen);
+                        // Q matrix is initially identity
+                        split_particle_state[idx*state_size +  3] = particle_rnumber(1.0);
+                        split_particle_state[idx*state_size +  4] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size +  5] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size +  6] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size +  7] = particle_rnumber(1.0);
+                        split_particle_state[idx*state_size +  8] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size +  9] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size + 10] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size + 11] = particle_rnumber(1.0);
+                        // log-stretching factors are initially 0
+                        split_particle_state[idx*state_size + 12] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size + 13] = particle_rnumber(0.0);
+                        split_particle_state[idx*state_size + 14] = particle_rnumber(0.0);
+                    }
+                }
+                else
+                {
                     for (partsize_t idx=0; idx < partsize_t(load_splitter.getMySize()); idx++)
                     {
                         // positions are uniformly distributed within cube
@@ -121,6 +147,7 @@ class particles_input_random: public abstract_particles_input<partsize_t, partic
                             split_particle_state[idx*state_size + cc] = gdist(rgen);
                     }
                 }
+            }
 
 
             /*************************************************/