pub fn inner_product_par<FX, PX, PY>(xs: &[PX], ys: &[PY]) -> FXwhere PX: PackedField<Scalar = FX>, PY: PackedField, FX: ExtensionField<PY::Scalar>,
Calculate inner product for potentially big slices of xs and ys. The number of elements in xs has to be less or equal to the number of elements in ys.