Improve error and logging messages

src/metatrain/utils/data/dataset.py

@@ -246,7 +246,7 @@
     """Returns the statistics of a dataset or subset as a string."""
 
     dataset_len = len(dataset)
-    stats = f"Dataset of size {dataset_len}"
+    stats = f"Dataset containing {dataset_len} structures"
     if dataset_len == 0:
         return stats
 
@@ -389,17 +389,35 @@
         or targets that are not present in the training set
     """
     # Check that system `dtypes` are consistent within datasets
-    desired_dtype = train_datasets[0][0].system.positions.dtype
-    msg = f"`dtype` between datasets is inconsistent, found {desired_dtype} and "
+    desired_dtype = None
     for train_dataset in train_datasets:
+        if len(train_dataset) == 0:
+            continue
+
         actual_dtype = train_dataset[0].system.positions.dtype
+        if desired_dtype is None:
+            desired_dtype = actual_dtype
+
         if actual_dtype != desired_dtype:
-            raise TypeError(f"{msg}{actual_dtype} found in `train_datasets`")
+            raise TypeError(
+                "`dtype` between datasets is inconsistent, "
+                f"found {desired_dtype} and {actual_dtype} in training datasets"
+            )
 
     for val_dataset in val_datasets:
+        if len(val_dataset) == 0:
+            continue
+
         actual_dtype = val_dataset[0].system.positions.dtype
+
+        if desired_dtype is None:
+            desired_dtype = actual_dtype
+
         if actual_dtype != desired_dtype:
-            raise TypeError(f"{msg}{actual_dtype} found in `val_datasets`")
+            raise TypeError(
+                "`dtype` between datasets is inconsistent, "
+                f"found {desired_dtype} and {actual_dtype} in validation datasets"
+            )
 
     # Get all targets in the training and validation sets:
     train_targets = get_all_targets(train_datasets)

src/metatrain/utils/data/readers/ase.py

@@ -7,13 +7,20 @@
 from metatensor.torch.atomistic import System, systems_to_torch
 
 
+def _wrapped_ase_io_read(filename):
+    try:
+        return ase.io.read(filename, ":")
+    except Exception as e:
+        raise ValueError(f"Failed to read '{filename}' with ASE: {e}") from e
+
+
 def read_systems_ase(filename: str) -> List[System]:
     """Store system informations using ase.
 
     :param filename: name of the file to read
     :returns: A list of systems
     """
-    return systems_to_torch(ase.io.read(filename, ":"), dtype=torch.float64)
+    return systems_to_torch(_wrapped_ase_io_read(filename), dtype=torch.float64)
 
 
 def read_energy_ase(filename: str, key: str) -> List[TensorBlock]:
@@ -23,7 +30,7 @@
     :param key: target value key name to be parsed from the file.
     :returns: TensorMap containing the energies
     """
-    frames = ase.io.read(filename, ":")
+    frames = _wrapped_ase_io_read(filename)
 
     properties = Labels("energy", torch.tensor([[0]]))
 
@@ -57,7 +64,7 @@
     :param key: target value key name to be parsed from the file.
     :returns: TensorMap containing the forces
     """
-    frames = ase.io.read(filename, ":")
+    frames = _wrapped_ase_io_read(filename)
 
     components = [Labels(["xyz"], torch.arange(3).reshape(-1, 1))]
     properties = Labels("energy", torch.tensor([[0]]))
@@ -117,7 +124,7 @@
 def _read_virial_stress_ase(
     filename: str, key: str, is_virial: bool = True
 ) -> List[TensorBlock]:
-    frames = ase.io.read(filename, ":")
+    frames = _wrapped_ase_io_read(filename)
 
     samples = Labels(["sample"], torch.tensor([[0]]))
     components = [

src/metatrain/utils/data/readers/readers.py

@@ -31,11 +31,11 @@ def _base_reader(
 ) -> List[Any]:
     if reader is None:
         try:
-            filesuffix = Path(filename).suffix
-            reader = DEFAULT_READER[filesuffix]
+            file_suffix = Path(filename).suffix
+            reader = DEFAULT_READER[file_suffix]
         except KeyError:
             raise ValueError(
-                f"File extension {filesuffix!r} is not linked to a default reader "
+                f"File extension {file_suffix!r} is not linked to a default reader "
                 "library. You can try reading it by setting a specific 'reader' from "
                 f"the known ones: {', '.join(AVAILABLE_READERS)} "
             )
@@ -171,7 +171,7 @@ def read_targets(
     This function uses subfunctions like :func:`read_energy` to parse the requested
     target quantity. Currently only `energy` is a supported target property. But, within
     the `energy` section gradients such as `forces`, the `stress` or the `virial` can be
-    added. Other gradients are silentlty irgnored.
+    added. Other gradients are silently ignored.
 
     :param conf: config containing the keys for what should be read.
     :returns: Dictionary containing a list of TensorMaps for each target section in the
@@ -191,13 +191,13 @@ def read_targets(
     for target_key, target in conf.items():
         target_info_gradients: List[str] = []
 
-        if target_key not in standard_outputs_list and not target_key.startswith(
-            "mtt::"
-        ):
+        is_standard_target = target_key in standard_outputs_list
+        if not is_standard_target and not target_key.startswith("mtt::"):
             raise ValueError(
-                f"Target names must either be one of {standard_outputs_list} "
-                "or start with `mtt::`."
+                f"Target name ({target_key}) must either be one of "
+                f"{standard_outputs_list} or start with `mtt::`."
             )
+
         if target["quantity"] == "energy":
             blocks = read_energy(
                 filename=target["read_from"],
@@ -213,14 +213,11 @@ def read_targets(
                         reader=target["forces"]["reader"],
                     )
                 except Exception:
-                    logger.warning(
-                        f"No Forces found in section {target_key!r}. "
-                        "Continue without forces!"
-                    )
+                    logger.warning(f"No forces found in section {target_key!r}.")
                 else:
                     logger.info(
-                        f"Forces found in section {target_key!r}. Forces are taken for "
-                        "training!"
+                        f"Forces found in section {target_key!r}, "
+                        "we will use this gradient to train the model"
                     )
                     for block, position_gradient in zip(blocks, position_gradients):
                         block.add_gradient(
@@ -230,7 +227,7 @@ def read_targets(
                     target_info_gradients.append("positions")
 
             if target["stress"] and target["virial"]:
-                raise ValueError("Cannot use stress and virial at the same time!")
+                raise ValueError("Cannot use stress and virial at the same time")
 
             if target["stress"]:
                 try:
@@ -240,14 +237,11 @@ def read_targets(
                         reader=target["stress"]["reader"],
                     )
                 except Exception:
-                    logger.warning(
-                        f"No Stress found in section {target_key!r}. "
-                        "Continue without stress!"
-                    )
+                    logger.warning(f"No stress found in section {target_key!r}.")
                 else:
                     logger.info(
-                        f"Stress found in section {target_key!r}. Stress is taken for "
-                        f"training!"
+                        f"Stress found in section {target_key!r}, "
+                        "we will use this gradient to train the model"
                     )
                     for block, strain_gradient in zip(blocks, strain_gradients):
                         block.add_gradient(parameter="strain", gradient=strain_gradient)
@@ -262,14 +256,11 @@ def read_targets(
                         reader=target["virial"]["reader"],
                     )
                 except Exception:
-                    logger.warning(
-                        f"No Virial found in section {target_key!r}. "
-                        "Continue without virial!"
-                    )
+                    logger.warning(f"No virial found in section {target_key!r}.")
                 else:
                     logger.info(
-                        f"Virial found in section {target_key!r}. Virial is taken for "
-                        f"training!"
+                        f"Virial found in section {target_key!r}, "
+                        "we will use this gradient to train the model"
                     )
                     for block, strain_gradient in zip(blocks, strain_gradients):
                         block.add_gradient(parameter="strain", gradient=strain_gradient)

tests/cli/test_train_model.py

@@ -77,7 +77,7 @@ def test_train(capfd, monkeypatch, tmp_path, output):
     assert "Training dataset:" in stdout_log
     assert "Validation dataset:" in stdout_log
     assert "Test dataset:" in stdout_log
-    assert "size 50" in stdout_log
+    assert "50 structures" in stdout_log
     assert "mean " in stdout_log
     assert "std " in stdout_log
     assert "[INFO]" in stdout_log

tests/utils/data/test_dataset.py

@@ -557,25 +557,26 @@ def test_check_datasets():
     # wrong dtype
     systems_qm9_32bit = [system.to(dtype=torch.float32) for system in systems_qm9]
     targets_qm9_32bit = {
-        k: [v.to(dtype=torch.float32) for v in l] for k, l in targets_qm9.items()
+        name: [tensor.to(dtype=torch.float32) for tensor in values]
+        for name, values in targets_qm9.items()
     }
     train_set_32_bit = Dataset.from_dict(
         {"system": systems_qm9_32bit, **targets_qm9_32bit}
     )
 
     match = (
         "`dtype` between datasets is inconsistent, found torch.float64 and "
-        "torch.float32 found in `val_datasets`"
+        "torch.float32 in validation datasets"
     )
     with pytest.raises(TypeError, match=match):
         check_datasets([train_set], [train_set_32_bit])
 
     match = (
         "`dtype` between datasets is inconsistent, found torch.float64 and "
-        "torch.float32 found in `train_datasets`"
+        "torch.float32 in training datasets"
     )
     with pytest.raises(TypeError, match=match):
-        check_datasets([train_set, train_set_32_bit], [val_set])
+        check_datasets([train_set, train_set_32_bit], [])
 
 
 def test_collate_fn():
@@ -651,7 +652,7 @@ def test_get_stats():
     stats = get_stats(dataset, dataset_info)
     stats_2 = get_stats(dataset_2, dataset_info)
 
-    assert "size 100" in stats
+    assert "100 structures" in stats
     assert "mtt::U0" in stats
     assert "energy" in stats_2
     assert "mean " in stats

tests/utils/data/test_readers.py

@@ -256,12 +256,12 @@ def test_read_targets_warnings(stress_dict, virial_dict, monkeypatch, tmp_path,
     caplog.set_level(logging.WARNING)
     read_targets(OmegaConf.create(conf))  # , slice_samples_by="system")
 
-    assert any(["No Forces found" in rec.message for rec in caplog.records])
+    assert any(["No forces found" in rec.message for rec in caplog.records])
 
     if stress_dict:
-        assert any(["No Stress found" in rec.message for rec in caplog.records])
+        assert any(["No stress found" in rec.message for rec in caplog.records])
     if virial_dict:
-        assert any(["No Virial found" in rec.message for rec in caplog.records])
+        assert any(["No virial found" in rec.message for rec in caplog.records])
 
 
 def test_read_targets_error(monkeypatch, tmp_path):

tox.ini

@@ -78,10 +78,10 @@ deps =
     build
     check-manifest
     twine
-allowlist_externals = bash
+allowlist_externals = rm
 commands_pre =
-    bash -c "if [ -e {toxinidir}/dist/*tar.gz ]; then unlink {toxinidir}/dist/*.whl; fi"
-    bash -c "if [ -e {toxinidir}/dist/*tar.gz ]; then unlink {toxinidir}/dist/*.tar.gz; fi"
+    rm -f {toxinidir}/dist/*.whl
+    rm -f {toxinidir}/dist/*.tar.gz
 commands =
     python -m build
     twine check dist/*.tar.gz dist/*.whl