An upgraded version of the generator BCVEGPY2.0 for hadronic production of Bc meson and its excited states

An upgraded version of the package BCVEGPY2.0: [C.-H. Chang, J.-X. Wang, X.-G. Wu, Comput. Phys. Common. 174 (2006) 241] is presented, which works under LINUX system and is named as BCVEGPY2.1. With the version and a GNU C compiler additionally, users may simulate the B-c-events in various experimental environments very conveniently. It has been manipulated in better modularity and code reusability (less cross communication among various modules) than BCVEGPY2.0 has. Furthermore, in the upgraded version a special execution is arranged as that the GNU command make compiles a requested code with the help of a master makefile in main code directory, and then builds an executable file with the default name run. Finally, this paper may also be considered as an erratum, i.e., typo errors in BCVEGPY2.0 and corrections accordingly have been listed.