The Align package provides functionality for aligning and mergin molecules. Molecules are aligned using a Maximum Common Substructure (MCS) search, which is used to find mappings between atom indices in the two molecules. Functionality is provided for sorting the mappings according to a scoring function, such as the root mean squared displacement of the alignment that is generated by the mapping.

Some examples:

import BioSimSpace as BSS

# Here we assume that we have already created two BioSimSpace molecules,
# mol0 and mol1.

# Find the best MCS mapping from mol0 to mol1.
mapping = BSS.Align.matchAtoms(mol0, mol1)

# Return a maximum of 10 matches, scored by RMSD and sorted from best to worst.
mappings = BSS.Align.matchAtoms(mol0, mol1, matches=10)

# Align mol0 to mol1 based on the best mapping. The molecule is aligned based
# on a root mean squared displacement fit to find the optimal translation vector
# (as opposed to merely taking the difference of centroids).
mol0 = BSS.Align.rmsdAlign(mol0, mol1, mapping)

# Merge the properties of the two molecules based on the atom mapping.
# The resulting "merged-molecule" can be used in free energy perturbation
# simulations.
merged = BSS.Align.merge(mol0, mol1, mappings)



matchAtoms(molecule0, molecule1[, …])

Find mappings between atom indices in molecule0 to those in molecule1.

rmsdAlign(molecule0, molecule1[, mapping, …])

Align atoms in molecule0 to those in molecule1 using the mapping between matched atom indices.

merge(molecule0, molecule1[, mapping, …])

Create a merged molecule from ‘molecule0’ and ‘molecule1’ based on the atom index ‘mapping’.