Fixed priorband_template.py example (#154)

neps/optimizers/multi_fidelity/successive_halving.py

@@ -105,7 +105,7 @@ def __init__(
         self.sample_default_first = sample_default_first
         self.sample_default_at_target = sample_default_at_target
 
-        assert self.pipeline_space.fidelity is not None
+        assert self.pipeline_space.fidelity is not None, "Fidelity parameter not set."
         self.min_budget = self.pipeline_space.fidelity.lower
         self.max_budget = self.pipeline_space.fidelity.upper
         self.eta = eta

neps/search_spaces/hyperparameters/numerical.py

@@ -119,6 +119,12 @@ def __init__(
                 f"{default_confidence}"
             )
 
+        if is_fidelity and (lower <= 0 or upper <= 0):
+            raise ValueError(
+                f"{_cls_name} parameter: fidelity parameter bounds error (log scale "
+                f"can't have bounds <= 0). Actual values: lower={lower}, upper={upper}"
+            )
+
         # Validate 'log' and 'is_fidelity' types to prevent configuration errors
         # from the YAML input
         for param, value in {"log": log, "is_fidelity": is_fidelity}.items():

neps_examples/template/priorband_template.py

@@ -48,7 +48,7 @@ def pipeline_space() -> dict:
             default=1e-3,  # a non-None value here acts as the mode of the prior distribution
         ),
         wd=neps.Float(
-            lower=0,
+            lower=1e-5,
             upper=1e-1,
             log=True,
             default=1e-3,

tests/test_yaml_search_space/correct_config.yaml

@@ -5,7 +5,7 @@ param_float1:
   is_fidelity: off
 
 param_int1:
-  lower: -3
+  lower: 3
   upper: 30
   log: false
   is_fidelity: on

tests/test_yaml_search_space/correct_config_including_types.yaml

@@ -6,7 +6,7 @@ param_float1:
 
 param_int1:
   type: integer
-  lower: -3
+  lower: 3
   upper: 30
   is_fidelity: True
 

tests/test_yaml_search_space/incorrect_fidelity_bounds_config.yaml

@@ -0,0 +1,22 @@
+param_float1:
+  lower: 0.00001
+  upper: 0.1
+  log: TRUE
+  is_fidelity: off
+
+param_int1:
+  lower: -3 # negative fidelity range
+  upper: 30
+  log: false
+  is_fidelity: on
+
+param_int2:
+  type: int
+  lower: 1E2
+  upper: 3e4
+  log: ON
+  is_fidelity: FALSE
+
+param_float2:
+  lower: 3.3e-5
+  upper: 1.5E-1

tests/test_yaml_search_space/test_search_space.py

@@ -19,7 +19,7 @@ def test_correct_yaml_file(path):
         assert isinstance(pipeline_space, dict)
         float1 = Float(0.00001, 0.1, log=True, is_fidelity=False)
         assert float1.__eq__(pipeline_space["param_float1"]) is True
-        int1 = Integer(-3, 30, log=False, is_fidelity=True)
+        int1 = Integer(3, 30, log=False, is_fidelity=True)
         assert int1.__eq__(pipeline_space["param_int1"]) is True
         int2 = Integer(100, 30000, log=True, is_fidelity=False)
         assert int2.__eq__(pipeline_space["param_int2"]) is True
@@ -143,3 +143,11 @@ def test_categorical_default_value_not_in_choices():
     with pytest.raises(SearchSpaceFromYamlFileError) as excinfo:
         pipeline_space_from_yaml(BASE_PATH + "default_value_not_in_choices_config.yaml")
     assert excinfo.value.exception_type == "ValueError"
+
+@pytest.mark.neps_api
+def test_incorrect_fidelity_parameter_bounds():
+    """Test if a ValueError is raised when the bounds of a fidelity parameter are
+    not correctly specified."""
+    with pytest.raises(SearchSpaceFromYamlFileError) as excinfo:
+        pipeline_space_from_yaml(BASE_PATH + "incorrect_fidelity_bounds_config.yaml")
+    assert excinfo.value.exception_type == "ValueError"