Fix paramter initialization

For sign_alpha=-1 old initialization fails

src/feature_creation/node/operator_nodes/allowed_operator_nodes/log/parameterized_log.cpp

@@ -267,13 +267,13 @@ void LogParamNode::initialize_params(double* params, const int depth) const
     if(depth >= nlopt_wrapper::MAX_PARAM_DEPTH)
     {
         val_ptr = _feats[0]->value_ptr();
-        params[1] = std::max(0.0, -1.0 * (*std::min_element(val_ptr, val_ptr + _n_samp)) + 1e-10);
+        params[1] = std::max(0.0, -1.0 * _sign_alpha * (*std::min_element(val_ptr, val_ptr + _n_samp, [this](double x1, double x2){return x1 * _sign_alpha < x2 * _sign_alpha;})) + 1e-10);
         return;
     }
     _feats[0]->initialize_params(params + 2, depth + 1);
 
     val_ptr = _feats[0]->value_ptr(params + 2);
-    params[1] = std::max(0.0, -1.0 * (*std::min_element(val_ptr, val_ptr + _n_samp)) + 1e-10);
+    params[1] = std::max(0.0, -1.0 * _sign_alpha * (*std::min_element(val_ptr, val_ptr + _n_samp, [this](double x1, double x2){return x1 * _sign_alpha < x2 * _sign_alpha;})) + 1e-10);
 }
 
 void LogParamNode::update_postfix(std::string& cur_expr, const bool add_params) const