Merge pull request #1609 from AlbinSou/optimizers

Add support for multiple param groups

avalanche/models/dynamic_optimizers.py

@@ -16,14 +16,220 @@
 """
 from collections import defaultdict
 
+import numpy as np
 
-def compare_keys(old_dict, new_dict):
-    not_in_new = list(set(old_dict.keys()) - set(new_dict.keys()))
-    in_both = list(set(old_dict.keys()) & set(new_dict.keys()))
-    not_in_old = list(set(new_dict.keys()) - set(old_dict.keys()))
-    return not_in_new, in_both, not_in_old
+from avalanche._annotations import deprecated
 
+colors = {
+    "END": "\033[0m",
+    0: "\033[32m",
+    1: "\033[33m",
+    2: "\033[34m",
+    3: "\033[35m",
+    4: "\033[36m",
+}
+colors[None] = colors["END"]
 
+
+def _map_optimized_params(optimizer, parameters, old_params=None):
+    """
+    Establishes a mapping between a list of named parameters and the parameters
+    that are in the optimizer, additionally,
+    returns the lists of:
+
+    returns:
+        new_parameters: Names of new parameters in the provided "parameters" argument,
+                        that are not in the old parameters
+        changed_parameters: Names and indexes of parameters that have changed (grown, shrink)
+        not_found_in_parameters: List of indexes of optimizer parameters
+                                 that are not found in the provided parameters
+    """
+
+    if old_params is None:
+        old_params = {}
+
+    group_mapping = defaultdict(dict)
+    new_parameters = []
+
+    found_indexes = []
+    changed_parameters = []
+    for group in optimizer.param_groups:
+        params = group["params"]
+        found_indexes.append(np.zeros(len(params)))
+
+    for n, p in parameters.items():
+        gidx = None
+        pidx = None
+
+        # Find param in optimizer
+        found = False
+
+        if n in old_params:
+            search_id = id(old_params[n])
+        else:
+            search_id = id(p)
+
+        for group_idx, group in enumerate(optimizer.param_groups):
+            params = group["params"]
+            for param_idx, po in enumerate(params):
+                if id(po) == search_id:
+                    gidx = group_idx
+                    pidx = param_idx
+                    found = True
+                    # Update found indexes
+                    assert found_indexes[group_idx][param_idx] == 0
+                    found_indexes[group_idx][param_idx] = 1
+                    break
+            if found:
+                break
+
+        if not found:
+            new_parameters.append(n)
+
+        if search_id != id(p):
+            if found:
+                changed_parameters.append((n, gidx, pidx))
+
+        if len(optimizer.param_groups) > 1:
+            group_mapping[n] = gidx
+        else:
+            group_mapping[n] = 0
+
+    not_found_in_parameters = [np.where(arr == 0)[0] for arr in found_indexes]
+
+    return (
+        group_mapping,
+        changed_parameters,
+        new_parameters,
+        not_found_in_parameters,
+    )
+
+
+def _build_tree_from_name_groups(name_groups):
+    root = _TreeNode("")  # Root node
+    node_mapping = {}
+
+    # Iterate through each string in the list
+    for name, group in name_groups.items():
+        components = name.split(".")
+        current_node = root
+
+        # Traverse the tree and construct nodes for each component
+        for component in components:
+            if component not in current_node.children:
+                current_node.children[component] = _TreeNode(
+                    component, parent=current_node
+                )
+            current_node = current_node.children[component]
+
+        # Update the groups for the leaf node
+        if group is not None:
+            current_node.groups |= set([group])
+            current_node.update_groups_upwards()  # Inform parent about the groups
+
+        # Update leaf node mapping dict
+        node_mapping[name] = current_node
+
+    # This will resolve nodes without group
+    root.update_groups_downwards()
+    return root, node_mapping
+
+
+def _print_group_information(node, prefix=""):
+    # Print the groups for the current node
+
+    if len(node.groups) == 1:
+        pstring = (
+            colors[list(node.groups)[0]]
+            + f"{prefix}{node.global_name()}: {node.groups}"
+            + colors["END"]
+        )
+        print(pstring)
+    else:
+        print(f"{prefix}{node.global_name()}: {node.groups}")
+
+    # Recursively print group information for children nodes
+    for child_name, child_node in node.children.items():
+        _print_group_information(child_node, prefix + "  ")
+
+
+class _ParameterGroupStructure:
+    """
+    Structure used for the resolution of unknown parameter groups,
+    stores parameters as a tree and propagates parameter groups from leaves of
+    the same hierarchical level
+    """
+
+    def __init__(self, name_groups, verbose=False):
+        # Here we rebuild the tree
+        self.root, self.node_mapping = _build_tree_from_name_groups(name_groups)
+        if verbose:
+            _print_group_information(self.root)
+
+    def __getitem__(self, name):
+        return self.node_mapping[name]
+
+
+class _TreeNode:
+    def __init__(self, name, parent=None):
+        self.name = name
+        self.children = {}
+        self.groups = set()  # Set of groups (represented by index) this node belongs to
+        self.parent = parent  # Reference to the parent node
+        if parent:
+            # Inform the parent about the new child node
+            parent.add_child(self)
+
+    def add_child(self, child):
+        self.children[child.name] = child
+
+    def update_groups_upwards(self):
+        if self.parent:
+            if self.groups != {None}:
+                self.parent.groups |= (
+                    self.groups
+                )  # Update parent's groups with the child's groups
+            self.parent.update_groups_upwards()  # Propagate the group update to the parent
+
+    def update_groups_downwards(self, new_groups=None):
+        # If you are a node with no groups, absorb
+        if len(self.groups) == 0 and new_groups is not None:
+            self.groups = self.groups.union(new_groups)
+
+        # Then transmit
+        if len(self.groups) > 0:
+            for key, children in self.children.items():
+                children.update_groups_downwards(self.groups)
+
+    def global_name(self, initial_name=None):
+        """
+        Returns global node name
+        """
+        if initial_name is None:
+            initial_name = self.name
+        elif self.name != "":
+            initial_name = ".".join([self.name, initial_name])
+
+        if self.parent:
+            return self.parent.global_name(initial_name)
+        else:
+            return initial_name
+
+    @property
+    def single_group(self):
+        if len(self.groups) == 0:
+            raise AttributeError(
+                f"Could not identify group for this node {self.global_name()}"
+            )
+        elif len(self.groups) > 1:
+            raise AttributeError(
+                f"No unique group found for this node {self.global_name()}"
+            )
+        else:
+            return list(self.groups)[0]
+
+
+@deprecated(0.6, "update_optimizer with optimized_params=None is now used instead")
 def reset_optimizer(optimizer, model):
     """Reset the optimizer to update the list of learnable parameters.
 
@@ -53,7 +259,14 @@ def reset_optimizer(optimizer, model):
     return optimized_param_id
 
 
-def update_optimizer(optimizer, new_params, optimized_params, reset_state=False):
+def update_optimizer(
+    optimizer,
+    new_params,
+    optimized_params=None,
+    reset_state=False,
+    remove_params=False,
+    verbose=False,
+):
     """Update the optimizer by adding new parameters,
     removing removed parameters, and adding new parameters
     to the optimizer, for instance after model has been adapted
@@ -64,72 +277,69 @@ def update_optimizer(optimizer, new_params, optimized_params, reset_state=False)
 
     :param new_params: Dict (name, param) of new parameters
     :param optimized_params: Dict (name, param) of
-        currently optimized parameters (returned by reset_optimizer)
-    :param reset_state: Wheter to reset the optimizer's state (i.e momentum).
-        Defaults to False.
+                             currently optimized parameters
+    :param reset_state: Whether to reset the optimizer's state (i.e momentum).
+                        Defaults to False.
+    :param remove_params: Whether to remove parameters that were in the optimizer
+                          but are not found in new parameters. For safety reasons,
+                          defaults to False.
+    :param verbose: If True, prints information about inferred
+                    parameter groups for new params
+
     :return: Dict (name, param) of optimized parameters
     """
-    not_in_new, in_both, not_in_old = compare_keys(optimized_params, new_params)
+    (
+        group_mapping,
+        changed_parameters,
+        new_parameters,
+        not_found_in_parameters,
+    ) = _map_optimized_params(optimizer, new_params, old_params=optimized_params)
+
     # Change reference to already existing parameters
     # i.e growing IncrementalClassifier
-    for key in in_both:
-        old_p_hash = optimized_params[key]
-        new_p = new_params[key]
+    for name, group_idx, param_idx in changed_parameters:
+        group = optimizer.param_groups[group_idx]
+        old_p = optimized_params[name]
+        new_p = new_params[name]
         # Look for old parameter id in current optimizer
-        found = False
-        for group in optimizer.param_groups:
-            for i, curr_p in enumerate(group["params"]):
-                if id(curr_p) == id(old_p_hash):
-                    found = True
-                    if id(curr_p) != id(new_p):
-                        group["params"][i] = new_p
-                        optimized_params[key] = new_p
-                        optimizer.state[new_p] = {}
-                    break
-        if not found:
-            raise Exception(
-                f"Parameter {key} expected but " "not found in the optimizer"
-            )
+        group["params"][param_idx] = new_p
+        if old_p in optimizer.state:
+            optimizer.state.pop(old_p)
+            optimizer.state[new_p] = {}
 
     # Remove parameters that are not here anymore
     # This should not happend in most use case
-    keys_to_remove = []
-    for key in not_in_new:
-        old_p_hash = optimized_params[key]
-        found = False
-        for i, group in enumerate(optimizer.param_groups):
-            keys_to_remove.append([])
-            for j, curr_p in enumerate(group["params"]):
-                if id(curr_p) == id(old_p_hash):
-                    found = True
-                    keys_to_remove[i].append((j, curr_p))
-                    optimized_params.pop(key)
-                    break
-        if not found:
-            raise Exception(
-                f"Parameter {key} expected but " "not found in the optimizer"
-            )
-
-    for i, idx_list in enumerate(keys_to_remove):
-        for j, p in sorted(idx_list, key=lambda x: x[0], reverse=True):
-            del optimizer.param_groups[i]["params"][j]
-            if p in optimizer.state:
-                optimizer.state.pop(p)
+    if remove_params:
+        for group_idx, idx_list in enumerate(not_found_in_parameters):
+            for j in sorted(idx_list, key=lambda x: x, reverse=True):
+                p = optimizer.param_groups[group_idx]["params"][j]
+                optimizer.param_groups[group_idx]["params"].pop(j)
+                if p in optimizer.state:
+                    optimizer.state.pop(p)
+                del p
 
     # Add newly added parameters (i.e Multitask, PNN)
-    # by default, add to param groups 0
-    for key in not_in_old:
+
+    param_structure = _ParameterGroupStructure(group_mapping, verbose=verbose)
+
+    # New parameters
+    for key in new_parameters:
         new_p = new_params[key]
-        optimizer.param_groups[0]["params"].append(new_p)
+        group = param_structure[key].single_group
+        optimizer.param_groups[group]["params"].append(new_p)
         optimized_params[key] = new_p
         optimizer.state[new_p] = {}
 
     if reset_state:
         optimizer.state = defaultdict(dict)
 
-    return optimized_params
+    return new_params
 
 
+@deprecated(
+    0.6,
+    "parameters have to be added manually to the optimizer in an existing or a new parameter group",
+)
 def add_new_params_to_optimizer(optimizer, new_params):
     """Add new parameters to the trainable parameters.