Data Layouts#

When representing a collection of irreps with multiplicities there are two ways to organize the data in memory:

  • (ir, mul) - Irreps are the outermost dimension.

  • (mul, ir) - Multiplicities are the outermost dimension. This is the layout used by e3nn.

Illustration of data layouts

In the example above, all the blocks have a multiplicity of 4. Given the dimension of the irreps it could correspond to the irreps “4x0e + 4x1e + 4x2e”.