Fusil has an aggressivity factor used to guess automatically best parameters to crash a program. Example with Mplayer project :

In 71 seconds, Fusil crashs Mplayer 10 times (steps 6, 25, 26, 30, ...). Aggressivity (blue line) starts at 0.0 and grow to 5% for first crash and finish at 13%. Fusil tries to keep aggressivity as low as possible, this is why aggressivity growth stops after a target crash (a success).

AutoMangle class configures MangleFile agent using aggressivity factor:

• [0.0; 0.25[ : operations = bit
• [0.25; 0.50[ : operations = bit, replace_value, special_values
• [0.50; 1.0[ : operations = bit, replace_value, special_values, insert_bytes, delete_bytes
• Operation count is also computed using aggressivity and input file size