  static inline int GetSliceIndex(const int dim, const int split_size,
                                  const int residual) {
    DCHECK_GT(split_size, 0);
    DCHECK_GE(dim, 0);
    if (residual == 0) return dim / split_size;
    const int offset = residual * (split_size + 1);
    if (dim < offset) {
      return dim / (split_size + 1);
    } else {
      return residual + ((dim - offset) / split_size);
    }
  }