Add HOWTO: Circular Convs

XLA convs natively do not support this, but you can always manually concat a kernel/2 per dim amount of data on the edges to achieve it at some data layout cost.

A minimal example in terms of default Linen nn.Conv and jnp.pad:

class CircularConv(nn.Module):
  features: int
  kernel_size: Union[int, Iterable[int]]
  @nn.compact
  def __call__(self, inputs):
    padding = [(0, 0)] + [(k//2, k//2) for k in self.kernel_size] + [(0, 0)]
    inputs = jnp.pad(inputs, padding, mode='wrap')
    return nn.Conv(self.features, self.kernel_size, padding='VALID')(inputs)

[marcvanzee]

@VolodyaCO interesting suggestion! If you think this would be generally useful, could you create a feature request issue proposing this?

[marcvanzee]

Closing this since @sgrigory implemented circular padding in #1661. Thanks @sgrigory!