   cudaMemset(numNeighbours, 0, g->numvertices * sizeof(int));
   cudaMemset(tra, 0, g->numvertices * sizeof(float));
   cudaMemset(swg, 0, g->numvertices * sizeof(float));
-  cudaMemset(speed, 0, g->numvertices * sizeof(float));
   cudaMemset(oldForceX, 0, g->numvertices * sizeof(float));
   cudaMemset(oldForceY, 0, g->numvertices * sizeof(float));
   cudaMemset(graphSwing, 0, sizeof(float));


  float dispX = 0.0;
  float dispY = 0.0;

  // Update speed of Graph.
  fa2UpdateSpeedGraph(*graphSwing, *graphTract, &graphSpeed);

        numNeighbours,
        tra,
        swg,
        oldForceX,
        oldForceY,
        graphSwing,
