CYANA Function: irnum
irnum(integer) = integer
Given the external residue number that is used to identify the residue in the input data files, this function returns the corresponding residue index. The inverse function, rnum is available, too.
The residues are indexed from 1 to nr according to the sequence declared in the sequence file. Note that the (external) residue number that is used to identify a residue in the input files can be different from the (internal) residue index.