The Warren-Cowely Parameter (WCP) for short range solution order is defined as:
$$\mathrm{WCP}_{ij} = 1 - \frac{Z_{ij}}{x_j \cdot Z_i}$$

where $Z_{ij}$ is the partial Coordination Number (CN) of j atoms around i, $Z_{i}$ is the total CN around i, and $ x_{j}$ is the nominal composition of j.

Consider a two component solution of $\ce{A}$ and $\ce{B}$. If $\mathrm{WCP}>0$, like neighbors are preferred, If $\mathrm{WCP}<0$, unlike neighbors are preferred.

If both of $\mathrm{WCP}_{AA}$ and $\mathrm{WCP}_{BB}$ are positive, which one is preferred?

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    $\begingroup$ Could you clarify what $Z_{ij}$ and $x_j$ are in your equations? Does your definition match the one in this paper: deepblue.lib.umich.edu/bitstream/handle/2027.42/29021/… $\endgroup$ – Tyberius Feb 18 '20 at 16:27
  • $\begingroup$ Dear @Tyberius I have updated my question, and added the definitions $\endgroup$ – user89031 Feb 18 '20 at 17:09
  • $\begingroup$ @Tyberius do you not have any idea about this question? I checked the parameter with the definition in the paper you introduced, they are identical $\endgroup$ – user89031 Feb 25 '20 at 23:33
  • $\begingroup$ I do not know for sure. It could be that $WCP_{AB} is what actually matters.$WCP_{AA}$ and $WCP_{BB}$ both positive seems to me like it implies that both components prefer like neighbors. I had hoped clarifying your question and introducing some terminology for people who aren't familiar (like myself) would encourage an answer. $\endgroup$ – Tyberius Feb 25 '20 at 23:48

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