Recently, I am trying to use the parameters in Forcite to reproduce the result of calculation on MATLAB.

However, I can not understand the rules of equivalencing. The problem is that I do not understand how it works to identify if the parameters "match" to our goal. In addition, I do not understand how does the numbers of bond type(last column) to match the following table:

~    ~   ! Any bond

-    ~   ! Single bond

:    ~   ! Aromatic bond

=    ~   ! Double bond

#    ~   ! Triple bond

As Figure 4. shows the bond equivalence table for pcff.off is simple having only two levels, the first being a specific description of the bond and the second being the first (and only) equivalence level. So, suppose, for example, a model contains a bond term that is described by the type sequence c5:c5 bond (that is, two c5 atoms connected by an aromatic bond), but the forcefield contains only a "cp_", "~", "cp_" bond term, then, based on the tables in Figures 3 and 4, the following search pattern would be followed:

Step down : search pattern : result

1 1 1         cp : cp         - no match

1 1 2         cp ~ cp         - no match

2 2 2         cp_ ~ cp_       - found match

>>>>>> How does it to be found match or no match?

And Why does the last number 1 match to the bond type ":" and the number 2 match to the "~" ?

Thank you.