the best one is presented at first, and it up to this number.
默认 10
minimum alignment score function
defult
L,0,-0.2
意思是打分机制方程中的f(x) = 0 + -0.2 *x (where x is the read length)
For a read of 75bp this would mean that a read can have a lowest
alignment score of -15 before an alignment would become invalid. This is roughly equal to 2 mismatches or ~2 indels of 1-2 bp in the read (or a combination thereof). The stringency can be set using the --score_min <func> function.
