When a reaction string is printed in Chemkin in different jobs, the ordering in which they are listed gets jumbled. For instance in 2 jobs, I can get:

CH3(17)+CH3(17)=H(2)+C2H5(27)                       7.845e+12 0.100     10.600   

and

CH3(17)+CH3(17)=C2H5(27)+H(2)                       7.845e+12 0.100     10.600  

Which are identical except for the ordering. This is correct but makes it difficult for the user when one has to search multiple permutations of a single reaction to identify it. I think we should try to make str(reaction) print the species in order of index.