diff --git a/releso/shape_parameterization.py b/releso/shape_parameterization.py
index 2982658..9b14a54 100644
--- a/releso/shape_parameterization.py
+++ b/releso/shape_parameterization.py
@@ -229,8 +229,10 @@ def apply_continuous_action(self, value: float) -> float:
         """
         delta = self.max_value - self.min_value
         descaled_value = ((value + 1.0) / 2.0) * delta
-        self.current_position = np.clip(
-            descaled_value + self.min_value, self.min_value, self.max_value
+        self.current_position = float(
+            np.clip(
+                descaled_value + self.min_value, self.min_value, self.max_value
+            )
         )
         return self.current_position
 
diff --git a/releso/util/caching.py b/releso/util/caching.py
index 7e5d963..9e449b8 100644
--- a/releso/util/caching.py
+++ b/releso/util/caching.py
@@ -6,6 +6,50 @@
 import numpy as np
 
 
+class CachedValue:
+    """A simple data structure to hold cached values."""
+
+    def __init__(self, value: list[str], error: int | bool = False):
+        self.value: list[str] = value
+        self.error: int | bool = error
+
+    def __len__(self):
+        return len(self.value)
+
+    def __getitem__(self, index: int):
+        """Default dunder functionality.
+
+        Args:
+            index (int): Index to retrieve from the cached value.
+
+        Returns:
+            Any: The requested item if found, otherwise raises an IndexError.
+        """
+        return self.value[index]
+
+    def get(self, index: int | list[int]):
+        """Retrieve items from the cached value.
+
+        Args:
+            index (int | list[int]): Index or list of indices to retrieve from the
+            cached value.
+
+        Returns:
+            Any: The requested item if found.
+        """
+        if isinstance(index, list):
+            return [self.value[i] for i in index]
+        return self.value[index]
+
+    def __bool__(self):
+        raise RuntimeError(
+            "CachedValue cannot be used in a boolean context. Use the 'error' attribute to check for errors."
+        )
+
+    def __iter__(self):
+        return iter(self.value)
+
+
 class RelesoSporCache:
     """A simple SQLite cache for storing SPOR results.
 
@@ -43,6 +87,7 @@ def main(args, logger, func_data):
                 func_data["cache"] = RelesoSporCache(
                     db_path="spor_cache.db",
                     example_data={"data_key1": "value1", "data_key2": "value2"},
+                    # error_handling=True, # optional, if you want to store error information as well
                 )
             if args.reset:
                 # don't touch the cache, only reset the other func_data entries
@@ -51,6 +96,9 @@ def main(args, logger, func_data):
             key = RelesoSporCache.make_cache_key(input_params)
             cached_value = func_data["cache"].get(key)
             if cached_value is not None:
+                if cached_value: # was an error thrown?
+                    # an error is indicated for this result
+                    pass
                 # Use cached value
                 pass
             else:
@@ -62,13 +110,31 @@ def main(args, logger, func_data):
                     key,
                     {"data_key1": result[0], "data_key2": result[1]},
                 )
+                # if error handling is enabled you can add the error information as well
+                # func_data["cache"].set(
+                #     key,
+                #     {"data_key1": result[0], "data_key2": result[1]},
+                #     error=error_occurred,
+                # )
 
 
+    You can use error handling to also store if an error occurred during the computation.
+    This can be useful to avoid repeated attempts of expensive computations that are likely
+    to fail. If error handling is enabled, you can set the "error" key in the value
+    dictionary to indicate if an error occurred. When retrieving from the cache, you can
+    check the "error" key to see if the cached value is valid or if it indicates a previous
+    error.
+
     Params:
         db_path (str): Path to the SQLite database file.
-        This file will be created if it does not exist.
-        The cache will store key-value pairs where keys are strings and values are JSON-serializable
-        dictionaries.
+            This file will be created if it does not exist.
+            The cache will store key-value pairs where keys are strings and values are
+            JSON-serializable dictionaries.
+        example_data (dict): An example dictionary that defines the structure of the
+            values to be stored in the cache. The keys of this dictionary will be used
+            as the columns in the SQLite table.
+        error_handling (bool): If True, caching will also store and retrieve info if an
+            error occurred. Default is False.
     """
 
     @staticmethod
@@ -94,18 +160,29 @@ def make_cache_key(
         key = json.dumps(normalized_args, sort_keys=True)
         return key
 
-    def __init__(self, db_path: str, example_data: dict):
+    def __init__(
+        self, db_path: str, example_data: dict, error_handling: bool = False
+    ):
         self.db_path = db_path
+        self.error_handling = error_handling
 
-        self.keys = example_data.keys()
+        self.keys = list(example_data.keys())
         self.value_accessor = ", ".join(f"{key}" for key in self.keys)
+        self.value_type = ["TEXT" for _ in self.keys]
         self.value_question_mark = ", ".join("?" for _ in self.keys)
+        if error_handling:
+            self.keys.append("error")
+            self.value_accessor += ", error"
+            self.value_type.append("INT")
+            self.value_question_mark += ", ?"
 
         self._initialize_db()
 
     def _initialize_db(self):
         """Initialize the SQLite database and create the cache table if it doesn't exist."""
-        table_definitions = ", ".join(f"{key} TEXT" for key in self.keys)
+        table_definitions = ", ".join(
+            f"{key} {type_}" for key, type_ in zip(self.keys, self.value_type)
+        )
         with sqlite3.connect(self.db_path) as conn:
             cursor = conn.cursor()
             cursor.execute(
@@ -113,27 +190,84 @@ def _initialize_db(self):
             )
             conn.commit()
 
-    def set(self, key: str, value: dict):
+    def _convert_value_to_database_values(self, value: dict) -> list[any]:
+        """Convert a value dictionary to a list of database values.
+
+        Args:
+            value (dict): The value dictionary to convert.
+
+        Returns:
+            list[any]: A list of values corresponding to the database columns.
+        """
+        ret_values = [
+            json.dumps(value[key]) for key in self.keys if key != "error"
+        ]
+        if self.error_handling:
+            ret_values.append(value.get("error", value.get("error", 0)))
+        return ret_values
+
+    def set(self, key: str, value: dict, error: bool | int = False):
         """Store a value in the cache.
 
+        If error handling is enabled, this method will also ensure that the "error" key is present
+        in the value dictionary. If the value is None and an error is indicated, it will create a
+        new dictionary with all keys set to -1 except for the "error" key, which will be set to
+        -1. This allows for storing error information even when the actual value is not available.
+
         Args:
             key (str): The key to store the value under.
             value (dict): The value to store, must be a dictionary with keys matching
                           the example data keys.
+            error (bool | int): Indicates if an error occurred during computation. Default is False.
         """
-        if not isinstance(value, dict) or value.keys() != self.keys:
+        if self.error_handling:
+            # if error handling is enabled, we need to ensure that the "error" key is present in the value dictionary
+            # if the value is None, we will create a new dictionary with the "error" key set to the error value and all
+            # other keys set to -1. This allows us to store error information even when the actual value is not available.
+            if value is None:
+                if bool(error):
+                    value = {}
+                    for k in self.keys:
+                        if k != "error":
+                            value[k] = -1
+                else:
+                    raise ValueError(
+                        f"Value must be a dictionary with keys: {self.keys}"
+                    )
+            # add error value to the value dictionary if it is not already present
+            if value.get("error") is None:
+                value["error"] = int(error)
+        # check if all values are present and if the keys match the example data keys
+        if not isinstance(value, dict) or list(value.keys()) != self.keys:
             raise ValueError(
-                f"Value must be a dictionary with keys: {self.keys}"
+                f"Value must be a dictionary with keys: {self.keys}, but has keys: {list(value.keys())}"
             )
         with sqlite3.connect(self.db_path) as conn:
             cursor = conn.cursor()
             cursor.execute(
                 f"INSERT OR REPLACE INTO spor_cache (key, {self.value_accessor}) VALUES (?, {self.value_question_mark})",
-                (key, *[json.dumps(value[key]) for key in self.keys]),
+                (key, *self._convert_value_to_database_values(value)),
             )
             conn.commit()
 
-    def get(self, key: str) -> list[dict] | None:
+    def _cached_value_from_row(self, row) -> CachedValue:
+        """Convert a database row to a CachedValue instance.
+
+        Args:
+            row (tuple): A tuple representing a row from the database.
+
+        Returns:
+            CachedValue: An instance of CachedValue containing the cached data.
+        """
+        print(row)
+        if self.error_handling:
+            value = [json.loads(r) for r in row[:-1]]
+        else:
+            value = [json.loads(r) for r in row]
+        error_value = row[-1] if self.error_handling else False
+        return CachedValue(value=value, error=error_value)
+
+    def get(self, key: str) -> CachedValue | None:
         """Retrieve a value from the cache.
 
         Args:
@@ -150,7 +284,7 @@ def get(self, key: str) -> list[dict] | None:
                     f"SELECT {self.value_accessor} FROM spor_cache WHERE key = ?",
                     (key,),
                 )
-                rows = cursor.fetchone()
-                return [json.loads(row) for row in rows] if rows else None
+                row = cursor.fetchone()
+                return self._cached_value_from_row(row) if row else None
         except sqlite3.OperationalError:
             return None