Method clone

include/cppoptlib/function_base.h:257–259

Exposes the stored interface for mode-downgrading converting construction into a weaker-mode `FunctionExpr`. Returns a deep-copied interface pointer so the caller owns independent lifetime; `FunctionExpr` itself does not implement `FunctionInterface` so this is not `virtual`.

  // lifetime; `FunctionExpr` itself does not implement
  // `FunctionInterface` so this is not `virtual`.
  std::unique_ptr<FunctionInterface<TScalar, TMode, TDimension>> clone() const {
    return ptr ? ptr->clone() : nullptr;
  }
};

// Deduction guide for FunctionExpr.