  I propose a straightforward generalization of the projection scheme for
elastic tensors introduced by Moakher and Norris [J. Elasticity 85, 215 (2006)]
that takes into account also rotations. The "closest" tensor of any desired
symmetry to the original tensor of lower symmetry is "closer" in this
generalized scheme. The method has an important application in the context of
the special quasirandom structure (SQS) method for the computational modeling
of alloys, whereby the supercell's symmetry, and therefore that of the tensors
representing its properties, is reduced with respect to the material's
underlying symmetry. The approach allows to extract the tensor components most
representative of the macroscopic symmetry of the material. Although the
approach is general, in the present case I apply it to the elastic tensor and
give numerical examples. Simple approximate analytical expressions for cubic
materials are also provided.
