message: Add comments for factory parameters
diff: @@ -148,7 +148,16 @@ public:
  std::shared_ptr<const LinOp> GKO_FACTORY_PARAMETER(
  generated_preconditioner, nullptr);
  + /**
  + * Dimension of the subspace S. Determines how many intermediate
  + * residuals are computed in each iteration.
  + */
  size_type GKO_FACTORY_PARAMETER(subspace_dim, 2u);
  +
  + /**
  + * Threshold to determine if Av_n and v_n are too close to being
  + * perpendicular.
  + */
  remove_complex<ValueType> GKO_FACTORY_PARAMETER(kappa, 0.7);
  };
  GKO_ENABLE_LIN_OP_FACTORY(Idr, parameters, Factory);
  