message: Implement additive identity
diff: @@ -985,6 +985,12 @@ mod alga_impls {
  self + right
  }
  }
  +
  + impl<N: Copy + Num, I: SpIndex> Identity<Additive> for CsVecI<N, I> {
  + fn identity() -> CsVecI<N, I> {
  + CsVecI::zero()
  + }
  + }
  }
  #[cfg(test)]
  