diff --git a/tests/googletest/feature_creation/feature_generation/test_abs_diff_node.cc b/tests/googletest/feature_creation/feature_generation/test_abs_diff_node.cc
index c5b4b7050946a222c4553a5dae2ca3f46bbbbf7d..56abea85b217f979fefd1b08bb308162a755cd05 100644
--- a/tests/googletest/feature_creation/feature_generation/test_abs_diff_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_abs_diff_node.cc
@@ -155,7 +155,7 @@ namespace
 
         EXPECT_STREQ(_abs_diff_test->unit().toString().c_str(), "m");
 
-        EXPECT_STREQ(_abs_diff_test->expr().c_str(), "||A - (B)| - (B)|");
+        EXPECT_STREQ(_abs_diff_test->expr().c_str(), "|(|(A) - (B)|) - (B)|");
         EXPECT_STREQ(_abs_diff_test->postfix_expr().c_str(), "0|1|abd|1|abd");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_add_node.cc b/tests/googletest/feature_creation/feature_generation/test_add_node.cc
index e329fb8cf3ca7c31cbeb1e9ba4198d6e5922bdbe..45607c4dedaef6e5706874d16fae2a11e2236175 100644
--- a/tests/googletest/feature_creation/feature_generation/test_add_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_add_node.cc
@@ -153,7 +153,7 @@ namespace
 
         EXPECT_STREQ(_add_test->unit().toString().c_str(), "m");
 
-        EXPECT_STREQ(_add_test->expr().c_str(), "[[A + B] + B]");
+        EXPECT_STREQ(_add_test->expr().c_str(), "[([(A) + (B)]) + (B)]");
         EXPECT_STREQ(_add_test->postfix_expr().c_str(), "0|1|add|1|add");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_cb_node.cc b/tests/googletest/feature_creation/feature_generation/test_cb_node.cc
index 83acfab40574cf3983873c3c8069034da701066e..53dd38d2bc92c2537e51cf4b7c8ed3a77cdf4b24 100644
--- a/tests/googletest/feature_creation/feature_generation/test_cb_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_cb_node.cc
@@ -140,7 +140,7 @@ namespace
 
         EXPECT_STREQ(_cb_test->unit().toString().c_str(), "m^3");
 
-        EXPECT_STREQ(_cb_test->expr().c_str(), "(A)^3");
+        EXPECT_STREQ(_cb_test->expr().c_str(), "[A]^3");
         EXPECT_STREQ(_cb_test->postfix_expr().c_str(), "0|cb");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_cbrt_node.cc b/tests/googletest/feature_creation/feature_generation/test_cbrt_node.cc
index 2576dfada19ee444b24e0906165bd841fd347d6a..dbcee4944307abe498a7b244433babdef0f197b8 100644
--- a/tests/googletest/feature_creation/feature_generation/test_cbrt_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_cbrt_node.cc
@@ -165,7 +165,7 @@ namespace
 
         EXPECT_STREQ(_cbrt_test->unit().toString().c_str(), "m^0.333333");
 
-        EXPECT_STREQ(_cbrt_test->expr().c_str(), "cbrt(A)");
+        EXPECT_STREQ(_cbrt_test->expr().c_str(), "cbrt[A]");
         EXPECT_STREQ(_cbrt_test->postfix_expr().c_str(), "0|cbrt");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_cos_node.cc b/tests/googletest/feature_creation/feature_generation/test_cos_node.cc
index 55818c6e43eb58dd2a7ce71ecf145a262d9f1801..1f15d3364c022deb90e8b4dd47e16e79b82bff2d 100644
--- a/tests/googletest/feature_creation/feature_generation/test_cos_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_cos_node.cc
@@ -141,7 +141,7 @@ namespace
 
         EXPECT_STREQ(_cos_test->unit().toString().c_str(), "Unitless");
 
-        EXPECT_STREQ(_cos_test->expr().c_str(), "cos(A)");
+        EXPECT_STREQ(_cos_test->expr().c_str(), "cos[A]");
         EXPECT_STREQ(_cos_test->postfix_expr().c_str(), "0|cos");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_exp_node.cc b/tests/googletest/feature_creation/feature_generation/test_exp_node.cc
index 5324318066178fbca62b3c65abcbb310fc37642e..495976817125533a80aa8c020a83c1c1d67c694a 100644
--- a/tests/googletest/feature_creation/feature_generation/test_exp_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_exp_node.cc
@@ -170,7 +170,7 @@ namespace
 
         EXPECT_STREQ(_exp_test->unit().toString().c_str(), "Unitless");
 
-        EXPECT_STREQ(_exp_test->expr().c_str(), "exp(A)");
+        EXPECT_STREQ(_exp_test->expr().c_str(), "exp[A]");
         EXPECT_STREQ(_exp_test->postfix_expr().c_str(), "0|exp");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_inv_node.cc b/tests/googletest/feature_creation/feature_generation/test_inv_node.cc
index 18433247d994dd3e31c8ef899974952f12addb36..3a90fed99a45fa99da85cd9f783493bbefdf0b16 100644
--- a/tests/googletest/feature_creation/feature_generation/test_inv_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_inv_node.cc
@@ -164,7 +164,7 @@ namespace
 
         EXPECT_STREQ(_inv_test->unit().toString().c_str(), "m^-1");
 
-        EXPECT_STREQ(_inv_test->expr().c_str(), "1.0 / (A)");
+        EXPECT_STREQ(_inv_test->expr().c_str(), "1.0 / [A]");
         EXPECT_STREQ(_inv_test->postfix_expr().c_str(), "0|inv");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_log_node.cc b/tests/googletest/feature_creation/feature_generation/test_log_node.cc
index 19ccd194b8e6d389207485e37ffedf185be7b885..575308fca8618d6b26528d0d56eac9e4dca99656 100644
--- a/tests/googletest/feature_creation/feature_generation/test_log_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_log_node.cc
@@ -264,7 +264,7 @@ namespace
 
         EXPECT_STREQ(_log_test->unit().toString().c_str(), "Unitless");
 
-        EXPECT_STREQ(_log_test->expr().c_str(), "log(A)");
+        EXPECT_STREQ(_log_test->expr().c_str(), "ln[A]");
         EXPECT_STREQ(_log_test->postfix_expr().c_str(), "0|log");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_neg_exp_node.cc b/tests/googletest/feature_creation/feature_generation/test_neg_exp_node.cc
index d8c9a87c8d3eb05dd5e0204246271c8c6b19b558..e1d6e02c62ed2ab08c9e76714bbc198bc8d9af9b 100644
--- a/tests/googletest/feature_creation/feature_generation/test_neg_exp_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_neg_exp_node.cc
@@ -170,7 +170,7 @@ namespace
 
         EXPECT_STREQ(_neg_exp_test->unit().toString().c_str(), "Unitless");
 
-        EXPECT_STREQ(_neg_exp_test->expr().c_str(), "exp[-1.0*(A)]");
+        EXPECT_STREQ(_neg_exp_test->expr().c_str(), "exp[-1.0 * (A)]");
         EXPECT_STREQ(_neg_exp_test->postfix_expr().c_str(), "0|nexp");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_sin_node.cc b/tests/googletest/feature_creation/feature_generation/test_sin_node.cc
index 69483e0d1cf7e394b4c933c94baed124832bb971..b80960aaa82ddab1617403fc37cf6c7ab5058de4 100644
--- a/tests/googletest/feature_creation/feature_generation/test_sin_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_sin_node.cc
@@ -141,7 +141,7 @@ namespace
 
         EXPECT_STREQ(_sin_test->unit().toString().c_str(), "Unitless");
 
-        EXPECT_STREQ(_sin_test->expr().c_str(), "sin(A)");
+        EXPECT_STREQ(_sin_test->expr().c_str(), "sin[A]");
         EXPECT_STREQ(_sin_test->postfix_expr().c_str(), "0|sin");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_six_pow_node.cc b/tests/googletest/feature_creation/feature_generation/test_six_pow_node.cc
index 19288a34560798c160f786a3efe228595f29ed6b..24cb76b05b2a0c02b8449381ac8b32f0cd30a296 100644
--- a/tests/googletest/feature_creation/feature_generation/test_six_pow_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_six_pow_node.cc
@@ -167,7 +167,7 @@ namespace
 
         EXPECT_STREQ(_six_pow_test->unit().toString().c_str(), "m^6");
 
-        EXPECT_STREQ(_six_pow_test->expr().c_str(), "(A)^6");
+        EXPECT_STREQ(_six_pow_test->expr().c_str(), "[A]^6");
         EXPECT_STREQ(_six_pow_test->postfix_expr().c_str(), "0|sp");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_sq_node.cc b/tests/googletest/feature_creation/feature_generation/test_sq_node.cc
index 44691a6ef81bf991f3bf1c7380ce11b025a44381..9591decbfd4a831773308c5e38aa3ddd5a67cbca 100644
--- a/tests/googletest/feature_creation/feature_generation/test_sq_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_sq_node.cc
@@ -127,7 +127,7 @@ namespace
 
         EXPECT_STREQ(_sq_test->unit().toString().c_str(), "m^2");
 
-        EXPECT_STREQ(_sq_test->expr().c_str(), "(A)^2");
+        EXPECT_STREQ(_sq_test->expr().c_str(), "[A]^2");
         EXPECT_STREQ(_sq_test->postfix_expr().c_str(), "0|sq");
     }
 }
diff --git a/tests/googletest/feature_creation/feature_generation/test_sqrt_node.cc b/tests/googletest/feature_creation/feature_generation/test_sqrt_node.cc
index 31659139e80d5525523b107969f2aefddd61dfee..e832f81148082208cd12cb53d41806cbdd1397ed 100644
--- a/tests/googletest/feature_creation/feature_generation/test_sqrt_node.cc
+++ b/tests/googletest/feature_creation/feature_generation/test_sqrt_node.cc
@@ -178,7 +178,7 @@ namespace
 
         EXPECT_STREQ(_sqrt_test->unit().toString().c_str(), "m^0.5");
 
-        EXPECT_STREQ(_sqrt_test->expr().c_str(), "sqrt(A)");
+        EXPECT_STREQ(_sqrt_test->expr().c_str(), "sqrt[A]");
         EXPECT_STREQ(_sqrt_test->postfix_expr().c_str(), "0|sqrt");
     }
 }
diff --git a/tests/googletest/feature_creation/parameterization/test_abs_diff_node.cc b/tests/googletest/feature_creation/parameterization/test_abs_diff_node.cc
index f2f32940bd4a2265463b2e3b42877b80be1b6951..15cfb063492d18c918636241ab03d92aa56f168a 100644
--- a/tests/googletest/feature_creation/parameterization/test_abs_diff_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_abs_diff_node.cc
@@ -48,7 +48,7 @@ namespace
 
             allowed_op_funcs::abs_diff(90, _phi[0]->value_ptr(), _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_abs_node.cc b/tests/googletest/feature_creation/parameterization/test_abs_node.cc
index c5113aaa1539898da8c848865ca4e8ac18c8e50c..6dffbe7c67f4d3eb63aae73b33ea5c050ec44356 100644
--- a/tests/googletest/feature_creation/parameterization/test_abs_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_abs_node.cc
@@ -38,7 +38,7 @@ namespace
 
             _prop = std::vector<double>(900, 0.0);
             allowed_op_funcs::abs(900, _phi[0]->value_ptr(), _alpha, _a, _prop.data());
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_add_node.cc b/tests/googletest/feature_creation/parameterization/test_add_node.cc
index b149c0a20d5aba2ea6ab5cd861043777ebd50942..5c4d53e1d84f6a432a40309211dca95ad62144dd 100644
--- a/tests/googletest/feature_creation/parameterization/test_add_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_add_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::add(90, _phi[0]->value_ptr(), _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_cb_node.cc b/tests/googletest/feature_creation/parameterization/test_cb_node.cc
index e505f2fb9692ffd824cdaea9aa79266906036aee..d5337cf68f8f8631044655dd116039ff42775914 100644
--- a/tests/googletest/feature_creation/parameterization/test_cb_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_cb_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::cb(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_cbrt_node.cc b/tests/googletest/feature_creation/parameterization/test_cbrt_node.cc
index 7699bee35d682f6438eb97d02604a4661cb14715..cd4bec4ce11ac3e99d769dc45c8e1d45965673a9 100644
--- a/tests/googletest/feature_creation/parameterization/test_cbrt_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_cbrt_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(900, 0.0);
             allowed_op_funcs::cbrt(900, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_cos_node.cc b/tests/googletest/feature_creation/parameterization/test_cos_node.cc
index f47bed4d47b56e9d5168e664d699e11447509208..b847915793e2e45ff1d94abb5f752d0264184216 100644
--- a/tests/googletest/feature_creation/parameterization/test_cos_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_cos_node.cc
@@ -52,7 +52,7 @@ namespace
             _prop = std::vector<double>(900, 0.0);
             allowed_op_funcs::cos(900, _phi[0]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_div_node.cc b/tests/googletest/feature_creation/parameterization/test_div_node.cc
index 0f0404f6bdce40ce85b0759278482263680fee94..67a59973e5e1ad1b49f9b24e723e0a10bb5606a5 100644
--- a/tests/googletest/feature_creation/parameterization/test_div_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_div_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::div(90, _phi[0]->value_ptr(), _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_exp_node.cc b/tests/googletest/feature_creation/parameterization/test_exp_node.cc
index 959e79ee52bc1e70a9801c03045408bef33bfd46..4b46bc6ee4cf10d1cce9d65aee1de5c14899e9cf 100644
--- a/tests/googletest/feature_creation/parameterization/test_exp_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_exp_node.cc
@@ -55,7 +55,7 @@ namespace
             _prop = std::vector<double>(900, 0.0);
             allowed_op_funcs::exp(900, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_inv_node.cc b/tests/googletest/feature_creation/parameterization/test_inv_node.cc
index 0d8cad18258006a4e97d9e235ec5c57569d1375a..5ad24ba5755714c80bf48a388352c8a1fa344da0 100644
--- a/tests/googletest/feature_creation/parameterization/test_inv_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_inv_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::inv(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_log_node.cc b/tests/googletest/feature_creation/parameterization/test_log_node.cc
index def50c0ddc0decd9dc7288a7e316bc8ff9ed2d6c..93823d21094f448fe212eceff35a4b684e882bd0 100644
--- a/tests/googletest/feature_creation/parameterization/test_log_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_log_node.cc
@@ -55,7 +55,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::log(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_mult_node.cc b/tests/googletest/feature_creation/parameterization/test_mult_node.cc
index 8db88335713a8a61553cadeeb5f8ad5bf1091561..b7b80fc296e3d72c6d5e17e4a784eb3b60410d2b 100644
--- a/tests/googletest/feature_creation/parameterization/test_mult_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_mult_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(900, 0.0);
             allowed_op_funcs::mult(900, _phi[0]->value_ptr(), _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_neg_exp_node.cc b/tests/googletest/feature_creation/parameterization/test_neg_exp_node.cc
index 3aca13416e62db9c0c0e4143fa072fb74e2993e6..ad102244ce68e2693436233f5b803ea97e34704d 100644
--- a/tests/googletest/feature_creation/parameterization/test_neg_exp_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_neg_exp_node.cc
@@ -55,7 +55,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::neg_exp(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_sin_node.cc b/tests/googletest/feature_creation/parameterization/test_sin_node.cc
index 4f2418d89670725763340aca8a5701f17e2cc8c6..2dbc59ce171dcb6716ba2b49a66c16d5dddde60a 100644
--- a/tests/googletest/feature_creation/parameterization/test_sin_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_sin_node.cc
@@ -52,7 +52,7 @@ namespace
             _prop = std::vector<double>(900, 0.0);
             allowed_op_funcs::sin(900, _phi[0]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_six_pow_node.cc b/tests/googletest/feature_creation/parameterization/test_six_pow_node.cc
index f1e3c20fdaa5247c4dc5627e7d2635cf726b7071..a2e3e10480694931f95688a4e75788803df87a78 100644
--- a/tests/googletest/feature_creation/parameterization/test_six_pow_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_six_pow_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::sixth_pow(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_sq_node.cc b/tests/googletest/feature_creation/parameterization/test_sq_node.cc
index fe80642ea16290b4f61423671a102f1a4f4cbf62..f850435398306242b0e272ab0cf455dfc5671e40 100644
--- a/tests/googletest/feature_creation/parameterization/test_sq_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_sq_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::sq(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_sqrt_node.cc b/tests/googletest/feature_creation/parameterization/test_sqrt_node.cc
index bc560ea1226e903cebeed7337b0fa26c0b096599..649bf1e6ce219abce7e1c9ee6707e0d6b63c49bb 100644
--- a/tests/googletest/feature_creation/parameterization/test_sqrt_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_sqrt_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::sqrt(90, _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/parameterization/test_sub_node.cc b/tests/googletest/feature_creation/parameterization/test_sub_node.cc
index 7582e533d32efb957a8e805179f07bbd594cd243..37ca108577d451c298f988a7b28f2cb5c7724a76 100644
--- a/tests/googletest/feature_creation/parameterization/test_sub_node.cc
+++ b/tests/googletest/feature_creation/parameterization/test_sub_node.cc
@@ -47,7 +47,7 @@ namespace
             _prop = std::vector<double>(90, 0.0);
             allowed_op_funcs::sub(90, _phi[0]->value_ptr(), _phi[1]->value_ptr(), _alpha, _a, _prop.data());
 
-            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, true);
+            nlopt_wrapper::set_objective("regression", _prop.data(), _task_sizes_train, 1, 1);
         }
 
         node_ptr _feat_1;
diff --git a/tests/googletest/feature_creation/utils/test_utils.cc b/tests/googletest/feature_creation/utils/test_utils.cc
index 637753e168a20925955e87623230085e10bd443f..653fa4115fd3855bcc9d430db2ea531e7ae2df3c 100644
--- a/tests/googletest/feature_creation/utils/test_utils.cc
+++ b/tests/googletest/feature_creation/utils/test_utils.cc
@@ -38,7 +38,7 @@ namespace
         EXPECT_EQ(test->type(), NODE_TYPE::ADD);
         EXPECT_EQ(test->rung(), 3);
         EXPECT_LT(abs(test->value()[1] - (std::exp(2.0) + 2.0)), 1e-10);
-        EXPECT_STREQ(test->expr().c_str(), "[exp([(A) / (C)]) + B]");
+        EXPECT_STREQ(test->expr().c_str(), "[(exp[[(A) / (C)]]) + (B)]");
     }
 
     TEST_F(FeatCreationUtilsTest, TestPhiSelFromFile)
@@ -72,12 +72,12 @@ namespace
         EXPECT_EQ(phi_sel[0]->type(), NODE_TYPE::MODEL_FEATURE);
         EXPECT_EQ(phi_sel[0]->rung(), 3);
         EXPECT_LT(abs(phi_sel[0]->value()[1] - (std::exp(2.0) + 2.0)), 1e-10);
-        EXPECT_STREQ(phi_sel[0]->expr().c_str(), "[exp([(A) / (C)]) + B]");
+        EXPECT_STREQ(phi_sel[0]->expr().c_str(), "[(exp[[(A) / (C)]]) + (B)]");
 
         EXPECT_EQ(phi_sel[5]->type(), NODE_TYPE::MODEL_FEATURE);
         EXPECT_EQ(phi_sel[5]->rung(), 3);
         EXPECT_LT(abs(phi_sel[5]->value()[1] - (std::exp(2.0) - 2.0)), 1e-10);
-        EXPECT_STREQ(phi_sel[5]->expr().c_str(), "[(exp([(A) / (C)])) - (B)]");
+        EXPECT_STREQ(phi_sel[5]->expr().c_str(), "[(exp[[(A) / (C)]]) - (B)]");
         boost::filesystem::remove("phi_sel.txt");
     }
 
@@ -106,12 +106,12 @@ namespace
         EXPECT_EQ(phi[0]->type(), NODE_TYPE::ADD);
         EXPECT_EQ(phi[0]->rung(), 3);
         EXPECT_LT(abs(phi[0]->value()[1] - (std::exp(2.0) + 2.0)), 1e-10);
-        EXPECT_STREQ(phi[0]->expr().c_str(), "[exp([(A) / (C)]) + B]");
+        EXPECT_STREQ(phi[0]->expr().c_str(), "[(exp[[(A) / (C)]]) + (B)]");
 
         EXPECT_EQ(phi[5]->type(), NODE_TYPE::SUB);
         EXPECT_EQ(phi[5]->rung(), 3);
         EXPECT_LT(abs(phi[5]->value()[1] - (std::exp(2.0) - 2.0)), 1e-10);
-        EXPECT_STREQ(phi[5]->expr().c_str(), "[(exp([(A) / (C)])) - (B)]");
+        EXPECT_STREQ(phi[5]->expr().c_str(), "[(exp[[(A) / (C)]]) - (B)]");
         boost::filesystem::remove("phi.txt");
     }
 }
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_lorentizan.py b/tests/pytest/test_feature_creation/test_parameterize/test_lorentizan.py
index f9ec0ca4d7f1952d88422f82d09068389ffcab39..18a0d281f48be328719b80107fde0fb0eda8b5b1 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_lorentizan.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_lorentizan.py
@@ -27,11 +27,12 @@ def test_lorentzian():
     test_data_1 = np.linspace(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20, 20]"), Unit())
 
-    feat_node = InvParamNode(SqNode(feat_1, 2, 1e-50, 1e50), 3, 1e-50, 1e50)
     prop = 21.4 / ((data_1 - 0.25) ** 2.0 + 7.1) - 1.478
+    set_objective("regression", prop, [900], 2, 2)
 
-    set_objective("regression", prop, [900], 2, True)
+    feat_node = InvParamNode(SqNode(feat_1, 2, 1e-50, 1e50), 3, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_abs.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_abs.py
index 698af8e4c550fc459657d4b63545db748af19186..e79719c3eafea2269c34883c8f2daf6ef61b011d 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_abs.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_abs.py
@@ -27,13 +27,12 @@ def test_param_abs_node():
     test_data_1 = np.linspace(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20, 20]"), Unit())
 
-    feat_node = AbsParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = -2.3 * np.abs(1.55 * data_1 + 0.8751) - 1.2
+    set_objective("regression", prop, [900], 1, 1)
 
-    set_objective("regression", prop, [900], 1, True)
-
+    feat_node = AbsParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_abs_diff.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_abs_diff.py
index e2cdd0fe7a7906aa53ade4612efe51171f3def76..82fa8227d443423bf225db8f1f4c14ab5e818ada 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_abs_diff.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_abs_diff.py
@@ -25,18 +25,18 @@ def test_param_abs_diff_node():
 
     data_1 = np.linspace(-20, 20, 900)
     test_data_1 = np.linspace(-19.99, 19.99, 100)
+    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20.0, 20.0]"), Unit())
 
     data_2 = np.linspace(-14.256, 18.6523, 900)
     test_data_2 = np.linspace(-16.256, 17.6523, 100)
-
-    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20.0, 20.0]"), Unit())
     feat_2 = FeatureNode(1, "x_a", data_2, test_data_2, Domain("[-20.0, 20.0]"), Unit())
-    feat_node = AbsDiffParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
 
     prop = -2.3 * np.abs(data_1 - (1.5 * data_2 + 0.8751)) - 1.2
-    set_objective("regression", prop, [900], 1, True)
+    set_objective("regression", prop, [900], 1, 1)
 
+    feat_node = AbsDiffParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_add.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_add.py
index de5d697df5309fde7ca297ec123354be22158727..259a2a7e03781d9be9a83dcad45f99c80911df09 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_add.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_add.py
@@ -24,20 +24,18 @@ def test_param_add_node():
 
     data_1 = np.linspace(-20, 20, 90)
     test_data_1 = np.linspace(-19.99, 19.99, 10)
+    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20.0, 20.0]"), Unit())
 
     data_2 = np.linspace(-14.256, 18.6523, 90)
     test_data_2 = np.linspace(-16.256, 17.6523, 10)
-
-    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20.0, 20.0]"), Unit())
     feat_2 = FeatureNode(1, "x_a", data_2, test_data_2, Domain("[-20.0, 20.0]"), Unit())
 
-    feat_node = AddParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
-
     prop = -2.3 * (data_1 + 1.5 * data_2) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = AddParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_cb.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_cb.py
index 49344208d7e16bb04f5be914284a3aba177c44d0..c8e95fbadc290ccbe0a2e045c14e9c929b98a65a 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_cb.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_cb.py
@@ -27,13 +27,12 @@ def test_param_cb_node():
     test_data_1 = np.linspace(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20, 20]"), Unit())
 
-    feat_node = CbParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = np.power(1.55 * data_1 + 0.8751, 3.0) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = CbParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_cbrt.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_cbrt.py
index 0e3f672f8bb941c8ae580b397b3c944121bb3955..d6ed3165612c138065a56338db47865f9d6c284d 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_cbrt.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_cbrt.py
@@ -27,13 +27,12 @@ def test_param_cbrt_node():
     test_data_1 = np.linspace(0.52145, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[0.5, 20]"), Unit())
 
-    feat_node = CbrtParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = np.cbrt(1.55 * data_1 + 0.8751) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = CbrtParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_cos.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_cos.py
index 86ca75196a19b20f972e8882566bf413497d1319..06d1825ca048848cd8aec5fea68b3bab3a5ee737 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_cos.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_cos.py
@@ -27,12 +27,10 @@ def test_param_cos_node():
     test_data_1 = np.linspace(-1.994 * np.pi, 1.994 * np.pi, 100)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("(-6.3, 6.3)"), Unit())
 
-    feat_node = CosParamNode(feat_1, 1, 1e-50, 1e50)
-
     prop = -1.1 * np.cos(1.25 * data_1 + 2.13) + 0.01578
+    set_objective("regression", prop, [900], 1, 1)
 
-    set_objective("regression", prop, [900], 1, True)
-
+    feat_node = CosParamNode(feat_1, 1, 1e-50, 1e50)
     feat_node.get_parameters(prop)
 
     assert check_feat_parmeters(feat_node, prop)
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_div.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_div.py
index d937bf04bb410638ea7d16b579e3fb3d3adf49a5..cdfc0c591e3b034c2717da259454118621325749 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_div.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_div.py
@@ -25,19 +25,16 @@ def test_param_div_node():
 
     data_1 = np.random.uniform(-2.50, 2.50, 900)
     test_data_1 = np.linspace(0.52145, 19.99, 10)
+    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-2.5, 20.5]"), Unit())
 
     data_2 = np.random.uniform(0.5, 5.0, 900)
     test_data_2 = np.linspace(0.41, 19.8432, 10)
-
-    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-2.5, 20.5]"), Unit())
     feat_2 = FeatureNode(1, "x_a", data_2, test_data_2, Domain("[0.5, 5.0]"), Unit())
 
-    feat_node = DivParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
-
     prop = 4.124 * data_1 / ((data_2 + 1.8751)) - 0.12
+    set_objective("regression", prop, [900], 1, 1)
 
-    set_objective("regression", prop, [900], 1, True)
-
+    feat_node = DivParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
 
     assert check_feat_parmeters(feat_node, prop)
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_exp.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_exp.py
index 1eda227b294ffd9806a9704f1ef412dd6b9cb06e..fefc4f16fc02e40f3e3a95455eaf51ca2237d648 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_exp.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_exp.py
@@ -27,13 +27,12 @@ def test_param_exp_node():
     test_data_1 = np.linspace(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-5.0, 5.0]"), Unit())
 
-    feat_node = ExpParamNode(feat_1, 1, 1e-50, 1e50)
-
     prop = np.exp(1.32 * data_1 + 0.8751) - 0.12
+    set_objective("regression", prop, [900], 10, 1)
 
-    set_objective("regression", prop, [900], 10, True)
-
+    feat_node = ExpParamNode(feat_1, 1, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_inv.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_inv.py
index 67a3617ea4cfa9f151ac169ac7762978639844cb..60b70a09d7fe59c3f20edafcd9a0c0b2f6a535cd 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_inv.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_inv.py
@@ -25,16 +25,14 @@ def test_param_inv_node():
 
     data_1 = np.linspace(0.5, 20, 90)
     test_data_1 = np.linspace(0.52145, 19.99, 10)
-
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[0.5, 20]"), Unit())
 
-    feat_node = InvParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = 1.0 / (1.55 * data_1 + 0.8751) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = InvParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_log.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_log.py
index 5458d29d2bbc3e6c6db2b9f9768774e586a072d6..3935cbfb5e2598a952b84f2c239e9660c19047a9 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_log.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_log.py
@@ -27,13 +27,12 @@ def test_param_log_node():
     test_data_1 = np.linspace(0.52145, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[0.5, 20]"), Unit())
 
-    feat_node = LogParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = -2.014 * np.log(1.15 * data_1 + 0.1387)
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = LogParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_neg_exp.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_neg_exp.py
index 7a91c74c9f51d5c3b401060c78166a27c8888f1a..c559cb98a8b4f9cde993883da99cbdf91dc63a3c 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_neg_exp.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_neg_exp.py
@@ -27,13 +27,12 @@ def test_param_neg_exp_node():
     test_data_1 = np.linspace(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-10, 10]"), Unit())
 
-    feat_node = NegExpParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = np.exp(-1.55 * data_1 + 0.8751) - 0.12
+    set_objective("regression", prop, [900], 1, 1)
 
-    set_objective("regression", prop, [900], 1, True)
-
+    feat_node = NegExpParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_sin.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_sin.py
index c1ba0c0cb584c59cdecee0ea16812fc52c921311..60bee7567542e3450e6894d5629b660d22cde267 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_sin.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_sin.py
@@ -27,12 +27,10 @@ def test_param_sin_node():
     test_data_1 = np.linspace(-1.994 * np.pi, 1.994 * np.pi, 100)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("(-6.3, 6.3)"), Unit())
 
-    feat_node = SinParamNode(feat_1, 1, 1e-50, 1e50)
-
     prop = -1.1 * np.sin(1.25 * data_1 + 2.13) + 0.01578
+    set_objective("regression", prop, [900], 1, 1)
 
-    set_objective("regression", prop, [900], 1, True)
-
+    feat_node = SinParamNode(feat_1, 1, 1e-50, 1e50)
     feat_node.get_parameters(prop)
 
     assert check_feat_parmeters(feat_node, prop)
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_six_pow.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_six_pow.py
index bbdd4db1ecea8879c3219886dbbc21892cdfb005..e4c82ac9ceb906ac5397af72d463bd31902227bf 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_six_pow.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_six_pow.py
@@ -27,13 +27,12 @@ def test_param_six_pow_node():
     test_data_1 = np.random.uniform(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-5.0, 5.0]"), Unit())
 
-    feat_node = SixPowParamNode(feat_1, 1, 1e-50, 1e50)
-
     prop = 1.55 * np.power(data_1 + 0.21, 6.0) - 0.12
+    set_objective("regression", prop, [900], 1, 1)
 
-    set_objective("regression", prop, [900], 1, True)
-
+    feat_node = SixPowParamNode(feat_1, 1, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_sq.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_sq.py
index 02a085940fd95cbc089abfb38bede7035ed5e6b3..2f0acb4b0400957926538d6aa73453cf0574f153 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_sq.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_sq.py
@@ -27,13 +27,12 @@ def test_param_sq_node():
     test_data_1 = np.linspace(-19.99, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20, 20]"), Unit())
 
-    feat_node = SqParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = np.power(1.55 * data_1 + 0.8751, 2.0) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = SqParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_sqrt.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_sqrt.py
index 6e410d63520c95904a0899f0148ddb61ef2f3ca2..1bf2ee471f053de0b388396a0130611f65bfffc0 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_sqrt.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_sqrt.py
@@ -27,13 +27,12 @@ def test_param_sqrt_node():
     test_data_1 = np.linspace(0.52145, 19.99, 10)
     feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[0.5, 20]"), Unit())
 
-    feat_node = SqrtParamNode(feat_1, 2, 1e-50, 1e50)
-
     prop = np.sqrt(1.55 * data_1 + 0.8751) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = SqrtParamNode(feat_1, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
+
     assert check_feat_parmeters(feat_node, prop)
 
 
diff --git a/tests/pytest/test_feature_creation/test_parameterize/test_param_sub.py b/tests/pytest/test_feature_creation/test_parameterize/test_param_sub.py
index 11dbbc10ae90645e15d7a30a926be68c65baeeca..5be22c5272fd8a349317941b0b3713d319ada672 100644
--- a/tests/pytest/test_feature_creation/test_parameterize/test_param_sub.py
+++ b/tests/pytest/test_feature_creation/test_parameterize/test_param_sub.py
@@ -24,22 +24,19 @@ def test_param_sub_node():
 
     data_1 = np.linspace(-20, 20, 90)
     test_data_1 = np.linspace(-19.99, 19.99, 10)
+    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20.0, 20.0]"), Unit())
 
     data_2 = np.linspace(-14.256, 18.6523, 90)
     test_data_2 = np.linspace(-16.256, 17.6523, 10)
-
-    feat_1 = FeatureNode(0, "t_a", data_1, test_data_1, Domain("[-20.0, 20.0]"), Unit())
     feat_2 = FeatureNode(1, "x_a", data_2, test_data_2, Domain("[-20.0, 20.0]"), Unit())
 
-    feat_node = SubParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
-
     prop = -2.3 * (data_1 - 1.5 * data_2) - 1.2
+    set_objective("regression", prop, [90], 1, 1)
 
-    set_objective("regression", prop, [90], 1, True)
-
+    feat_node = SubParamNode(feat_1, feat_2, 2, 1e-50, 1e50)
     feat_node.get_parameters(prop)
-    check_feat_parmeters(feat_node, prop)
 
+    assert check_feat_parmeters(feat_node, prop)
 
 if __name__ == "__main__":
     test_param_sub_node()