def flow_trajectories(vertices, triangles, flow_file, steps=10, timestep=5):
"""
Compute the positive mass stiffness surface flow of a surface mesh.
Parameters:
- - - - -
vertices: float array
list of vertices in mesh
triangles: int array
list of faces in mesh
flow_file: string
file (memory map) in which to save flow lines
steps: int
number of diffusion steps
timestep: int
diffusion time
"""
# initialize flow object
tri_mesh_flow = TriMeshFlow_Vtk(triangles, vertices)
# compute final flow surface
points = tri_mesh_flow.positive_mass_stiffness_smooth(steps,
timestep,
flow_file=flow_file)
# get flow trajectory for each mesh vertex
flow_lines = tri_mesh_flow.get_vertices_flow()
return flow_lines
