The qualvector is an Arachne module consisting of a vector (or vec) of quality scores, in the form of C++ chars. Qualvectors are used to represent the quality scores of DNA sequences, including reads and contigs.
Qualvectors assume that the quality score is an integer value. They also use char objects rather than ints in order to save space (1 byte per base, rather than 4) which restricts the values to the range [0, 255]. Quality scores in char format will not be human-readable in output; they must be re-cast as ints.