by_for:  undefined=2398740, defined=9601260
by_grep: undefined=2398740, defined=9601260
by_diff: undefined=2398740, defined=9601260
Benchmark: running bydiff, byfor, bygrep for at least 600 CPU seconds...
    bydiff: 606 wallclock secs (604.93 usr +  0.11 sys = 605.04 CPU) @  0.08/s (n=51)
     byfor: 625 wallclock secs (623.32 usr +  0.09 sys = 623.41 CPU) @  0.06/s (n=40)
    bygrep: 604 wallclock secs (602.22 usr +  0.07 sys = 602.29 CPU) @  0.04/s (n=25)
       s/iter bygrep  byfor bydiff
bygrep   24.1     --   -35%   -51%
byfor    15.6    55%     --   -24%
bydiff   11.9   103%    31%     --