frequency_map

• type: major action command.
• function: compute frequency map from tracking Note that the number of turns tracked is set by the run_control command.

&frequency_map
    STRING output = NULL;
    double xmin = -0.1;
    double xmax = 0.1;
    double ymin = 1e-6;
    double ymax = 0.1;
    double delta_min = 0;
    double delta_max = 0;
    long nx = 21;
    long ny = 21;
    long ndelta = 1;
    long verbosity = 1;
    long include_changes = 0;
&end

• output -- The (incomplete) name of an SDDS file to send output to. Recommended value: ``%s.fma''. For the parallel version, particles will be listed in essentially random order. If needed, sddssort can be used to sort particles by initial coordinates.
• xmin, xmax -- Limits of grid of initial x coordinates for tracking.
• ymin, ymax -- Limits of grid of initial y coordinates for tracking. ymin should typically be a small, positive value so that there is some betatron oscillation from which to get the tune.
• delta_min, delta_max -- Limits of grid of initial $\delta$ coordinates for tracking. Not that particles are not centered around the dispersive closed orbit. Hence, the tracking is appropriate to simulation of dynamics from a touschek scattering event.
• nx -- Number of values of x coordinate in the grid.
• ny -- Number of values of y coordinate in the grid.
• ndelta -- Number of values of $\delta$ coordinate in the grid.
• verbosity -- If nonzero, prints possibly useful information while running.
• include_changes -- If nonzero, then computes not only the tunes, but also the changes in the tunes. This is expressed in terms of the diffusion, which is defined as
  

  $$d = \log \left(\Delta\nu_x^2 + \Delta\nu_y^2\right)$$ (1)

  
  
  Use of this feature results in a doubling of the number of turns tracked.