7.67 tune_footprint

&tune_footprint  
    STRING delta_output = NULL,  
    STRING xy_output = NULL,  
    double xmin =  -0.02,  
    double xmax =  0.02,  
    double ymin =  1e-6,  
    double ymax =  0.02,  
    double x_for_delta = 1e-6,  
    double y_for_delta = 1e-6,  
    double delta_min = 0,  
    double delta_max = 0,  
    long ndelta = 21,  
    long separate_xy_for_delta =  0;  
    long nx = 20,  
    long ny = 21,  
    long verbosity = 1,  
    long quadratic_spacing = 1,  
    long compute_diffusion = 1;  
    long diffusion_rate_limit = -5,  
    long immediate = 0  
    long filtered_output = 1;  
    long ignore_half_integer = 0;  
&end

This command makes available the following quantities for optimization. All quantities are limited by particle survival, crossing of integer and half-integer resonances, and the diffusion rate limit.

Typically, one strives to minimize FP.nuxSpreadChrom,FP.nuySpreadChrom, FP.nuxSpreadAmp, FP.nuySpreadAmp, FP.diffusionRateMaxChrom, and/or FP.diffusionRateMaxAmp while maximizing FP.deltaLimit, FP.xSpread, and/or FP.ySpread, and ensuring that FP.xyArea, at minimum, doesn’t decrease. I.e., one wants the maximum stable region for momentum and position deviations with the minimum spread in tunes and minimum diffusion.

twiss_analysis