I’d suggest using bin/level_calc.py instead… because Ferrero_Rocher/ramp_calc.py is old and less accurate and harder to use, and the only extra thing it offers is pulse frequency modulation to make the low end of the ramp look smoother.
If you aren’t using a single-channel driver with both PWM and PFM, use bin/level_calc.py instead.
For example, a FET+7135 driver with a single XP-L:
(~/src/torches/trunk/)-]> ./bin/level_calc.py
How many total levels do you want? (4) 64
Lowest visible PWM level, for moon mode: (6) 1
How bright is moon mode, in lumens? (0.25) 8
How bright is the highest level, in lumens? (1000) 1500
Use dual PWM? [y/n] (n) y
Second channel, lowest visible PWM level: (6) 3
Second channel, how bright is the lowest mode, in lumens? (0.25) 0.25
Second channel, how bright is maximum, in lumens? (140) 140
1: visually 0.63 (0.25 lm): 0.00/255, 3.00/255
2: visually 0.80 (0.52 lm): 0.00/255, 3.48/255
3: visually 0.97 (0.92 lm): 0.00/255, 4.21/255
...
62: visually 11.10 (1369.01 lm): 208.87/255, 255.00/255
63: visually 11.28 (1433.51 lm): 219.85/255, 255.00/255
64: visually 11.45 (1500.00 lm): 255.00/255, 0.00/255
PWM1/FET values: 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,3,6,9,12,15,18,22,26,30,34,38,43,48,53,58,63,69,75,81,88,95,102,109,117,124,133,141,150,159,168,178,188,198,209,220,255
PWM2/7135 values: 3,3,4,5,7,8,11,14,17,21,26,31,38,45,53,62,72,83,95,109,124,140,157,176,196,218,241,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,0