why about this?

[qiaozhiyi]

./include/difacto/loss.h: In member function ‘virtual difacto::real_t difacto::Loss::Evaluate(const real_t*, difacto::SArray&) const’:
./include/difacto/loss.h:63:23: error: ‘exp’ was not declared in this scope
63 | objv += log(1 + exp(- y * pred[i]));
| ^~~
./include/difacto/loss.h:63:15: error: ‘log’ was not declared in this scope; did you mean ‘long’?
63 | objv += log(1 + exp(- y * pred[i]));
| ^~~
| long