ction(index_i, dt);</div><div class="line"><a name="l00285"></a><span class="lineno">  285</span>&#160;                this-&gt;force_from_fluid_[index_i] += viscous_force_from_fluid_[index_i];</div><div class="line"><a name="l00286"></a><span class="lineno">  286</span>&#160;                this-&gt;acc_prior_[index_i] += viscous_force_from_fluid_[index_i] / this-&gt;particles_-&gt;ParticleMass(index_i);</div><div class="line"><a name="l00287"></a><span class="lineno">  287</span>&#160;            };</div>