Function conv3d_backward_dx 

pub fn conv3d_backward_dx<T: Triton, D: Num, const KD: i32, const KH: i32, const KW: i32, const STRIDE_D: i32, const STRIDE_H: i32, const STRIDE_W: i32, const PAD_D: i32, const PAD_H: i32, const PAD_W: i32, const BLOCK_OW: i32>(
    dy_ptr: T::Pointer<D>,
    w_ptr: T::Pointer<D>,
    dx_ptr: T::Pointer<D>,
    _B: i32,
    C_IN: i32,
    C_OUT: i32,
    Dv: i32,
    H: i32,
    W: i32,
    OD: i32,
    OH: i32,
    OW: i32,
)
where
    T::I32Tensor: Tensor<i32, 1> + Comparison<i32, BoolTensor = T::BoolTensor>,
    T::BoolTensor: BitAnd<Output = T::BoolTensor>,
    T::Pointer<D>: AddOffsets<i32, 1, T::I32Tensor, Output = T::Tensor<T::Pointer<D>>>,

3-D convolution backward pass — gradient with respect to input (dx).

Grid: pid = (((b * C_OUT + c_out) * OD + od) * OH + oh) * num_ow_tiles + ow_tile

Scatters gradient via atomic_add to handle overlapping receptive fields. Padding positions are skipped.