v3_add(&(aj->f),&(aj->f),&force);
 
        /* virial */
-       virial_calc(aj,&force,&(exchange->dist_ij));
+       virial_calc(ai,&force,&(exchange->dist_ij));
 
 #ifdef DEBUG
 if(moldyn->time>DSTART&&moldyn->time<DEND) {
        exchange=&(params->exchange);
        kcount=exchange->kcount;
 
-       if(kcount>ALBE_MAXN)
+       if(kcount>ALBE_ORIG_MAXN)
                printf("FATAL: neighbours!\n");
 
        /* d_ik2 */
 }
 #endif
 
+       /* virial */
+       virial_calc(ai,&force,&dist_ij);
+
        /* force contribution to atom i */
        v3_scale(&force,&force,-1.0);
        v3_add(&(ai->f),&(ai->f),&force);
 
-       /* virial */
-       virial_calc(ai,&force,&dist_ij);
-
        /* derivative wrt k */
        v3_scale(&force,&dist_ik,-1.0*dfcg); // dri rik = - drk rik
        v3_scale(&tmp,&dcosdrk,fcdg);
 }
 #endif
 
+       /* virial */
+       virial_calc(ai,&force,&dist_ik);
+
        /* force contribution to atom i */
        v3_scale(&force,&force,-1.0);
        v3_add(&(ai->f),&(ai->f),&force);
 
-       /* virial */
-       virial_calc(ai,&force,&dist_ik);
-       
        /* increase k counter */
        exchange->kcount++;