Local Warren-Cowley parameters calculation

[YuanqiYang00]

I noticed that mdapy can compute the global Warren-Cowley parameters, but sometimes we are more interested in the local chemical environment. For example, my system contains three types of atoms: Ni (type 1), Co (type 2), and Cr (type 3), and it tends to form Ni-Ni and Co-Cr clusters. Therefore, would it be possible to provide a feature that allows users to compute pairwise Warren-Cowley parameters for specific atom types and assign the results to each particle?

For example, I could obtain the result by using the following command:
cal_local_warren_cowley_parameter(neighbor_type=[1,3,2], rc=2.8),
where [1,3,2] specifies that the Warren-Cowley coefficients should be calculated for pairs 1-1 (Ni-Ni), 2-3 (Co-Cr), and 3-2 (Cr-Co), with a cutoff radius of 2.8 Å.

Thank you for considering this request.

[mushroomfire]

Hi @YuanqiYang00 I have implemented it in mdapy dev version. The usage is simple:

# Cutoff neighbor
system.cal_local_warren_cowley_parameter(["1-2", "2-3"], rc=3.)
# Voronoi neighbor
system.cal_local_warren_cowley_parameter(["1-2", "2-3"], use_voronoi=True)

It will generate "1-2" and "2-3" atom properties, with defaults value of -10000 for non-reference type.