Optimal coefficient in movemesh

Dear all, how to choose the optimal coefficient ‘dt’ when moving a mesh
Th = movemesh(Th,[x+dtvx,y+dtvy]);
Thank you in advance!

Well, there is no optimal value… it all depends on how you want to move the mesh.

I am looking for a domain realizing the minimum of a function in a “shape optimization problem”
and I am trying to use a line search method

Then your optimization algorithm should give you the proper value for dt.

The algorithm gives only the deformation field (vx, vy)