diff --git a/pytools/__init__.py b/pytools/__init__.py
index d5b8d8e9feb525a61ef5fdabeb10a671cd44b211..c7bb9d59dcb45188656cfd0e3e28a71925a1fefe 100644
--- a/pytools/__init__.py
+++ b/pytools/__init__.py
@@ -74,6 +74,7 @@ Memoization
 .. autofunction:: memoize_in
 .. autofunction:: keyed_memoize_on_first_arg
 .. autofunction:: keyed_memoize_method
+.. autofunction:: keyed_memoize_in
 
 Argmin/max
 ----------
@@ -914,6 +915,41 @@ class memoize_in:  # noqa
 
         return new_inner
 
+
+class keyed_memoize_in:  # noqa
+    """Like :class:`memoize_in`, but additionally uses a function *key* to
+    compute the key under which the function result is memoized.
+
+    :arg key: A function receiving the same arguments as the decorated function
+        which computes and returns the cache key.
+
+    .. versionadded :: 2021.2.1
+    """
+
+    def __init__(self, container, identifier, key):
+        try:
+            memoize_in_dict = container._pytools_keyed_memoize_in_dict
+        except AttributeError:
+            memoize_in_dict = {}
+            object.__setattr__(container, "_pytools_keyed_memoize_in_dict",
+                    memoize_in_dict)
+
+        self.cache_dict = memoize_in_dict.setdefault(identifier, {})
+        self.key = key
+
+    def __call__(self, inner):
+        @wraps(inner)
+        def new_inner(*args):
+            key = self.key(*args)
+            try:
+                return self.cache_dict[key]
+            except KeyError:
+                result = inner(*args)
+                self.cache_dict[key] = result
+                return result
+
+        return new_inner
+
 # }}}
 
 
diff --git a/pytools/version.py b/pytools/version.py
index b431cafddb6c25c285c9046eaf4bbf749911478e..fc538bf6b12a3c52bcbb8c65fc0d92819e5c2836 100644
--- a/pytools/version.py
+++ b/pytools/version.py
@@ -1,3 +1,3 @@
-VERSION = (2021, 2)
+VERSION = (2021, 2, 1)
 VERSION_STATUS = ""
 VERSION_TEXT = ".".join(str(x) for x in VERSION) + VERSION_STATUS