# OEAssignAromaticFlags¶

void OEAssignAromaticFlags(OEMolBase &mol,
unsigned int model=OEAroModel::OpenEye,
bool clearflags=true, unsigned int maxpath=0,
bool prune=false)


Perceives the aromatic atoms and bonds of a molecule. The assigned atom and bond aromaticity can be accessed by OEAtomBase.IsAromatic and OEBondBase.IsAromatic methods, respectively.

model
The parameter that specifies that aromaticity model that are perceived by the OEAssignAromaticFlags function. The default aromaticity ‘model’ is OEAroModel.OpenEye. Other predefined aromaticity models provided by OEChem TK include OEAroModel.Daylight, OEAroModel.Tripos, OEAroModel.MMFF and OEAroModel.MDL that represent the Daylight, Tripos, MMFF and MDL definitions, respectively.
clearflags
The parameter that specifies whether to clear the aromaticity flags by calling OEClearAromaticFlags prior to re-perceiving the aromaticity. Newly created molecules that have not had their aromaticity assigned yet can specify false, for a very small performance advantage.
maxpath
The parameter that specifies the maximum path length to consider an aromatic cycle, or zero (the default) to specify no upper bound on aromatic cycle length. Some formal models of aromaticity use the value six, limiting aromaticity to six membered rings like benzene or pyridine.
prune
The parameter that specifies whether or not to run a post-processing step to consider rings with exo-double bonds as not aromatic. This is also required by some formal models of aromaticity.