pub fn bottleneck_std<D: Float + 'static>(
c: usize,
shortcut: bool,
) -> impl Fn(SymTensor) -> SymTensorExpand description
conv(c → c//2, k=3) → conv(c//2 → c, k=3).
Matches ultralytics.nn.modules.block.Bottleneck(k=(3,3), e=0.5) defaults.