Function lppool2d_backward 

pub fn lppool2d_backward<T: Triton, D: Float, const KH: i32, const KW: i32, const STRIDE_H: i32, const STRIDE_W: i32, const BLOCK_OW: i32>(
    dy_ptr: T::Pointer<D>,
    x_ptr: T::Pointer<D>,
    y_ptr: T::Pointer<D>,
    dx_ptr: T::Pointer<D>,
    _B: i32,
    C: i32,
    H: i32,
    W: i32,
    OH: i32,
    OW: i32,
    p: f32,
)
where
    T::I32Tensor: Tensor<i32, 1> + Comparison<i32, BoolTensor = T::BoolTensor>,
    T::Pointer<D>: AddOffsets<i32, 1, T::I32Tensor, Output = T::Tensor<T::Pointer<D>>>,

2-D Lp-norm pooling backward pass.

dx_i = dy * sign(x_i) * (|x_i| / max(y, ε))^(p-1) / max(y, ε).

dx must be zero-initialised before launch.