not use momory to store nnz statistics

Author: ericliu8168

libmultilabel/linear/tree.py

@@ -149,7 +149,7 @@ def count(node):
     total_memory = psutil.virtual_memory().total 
     print(f'Your system memory is: {total_memory / (1024**3):.3f} GB')
 
-    model_size = get_estimated_model_size(root, num_nodes)
+    model_size = get_estimated_model_size(root)
     print(f'The estimated tree model size is: {model_size / (1024**3):.3f} GB')
 
     if (total_memory <= model_size):
@@ -208,24 +208,21 @@ def _build_tree(label_representation: sparse.csr_matrix, label_map: np.ndarray,
     return Node(label_map=label_map, children=children)
 
 
-def get_estimated_model_size(root, num_nodes):
-    num_nnz_feat, num_branches = np.zeros(num_nodes), np.zeros(num_nodes)
-    num_nodes = 0
+def get_estimated_model_size(root):
+    total_num_weights = 0
+
     def collect_stat(node: Node):
-        nonlocal num_nodes
-        num_nnz_feat[num_nodes] = node.num_nnz_feat
+        nonlocal total_num_weights
 
         if node.isLeaf():
-            num_branches[num_nodes] = len(node.label_map)
+            total_num_weights += len(node.label_map) * node.num_nnz_feat
         else:
-            num_branches[num_nodes] = len(node.children)
-        
-        num_nodes += 1
+            total_num_weights += len(node.children) * node.num_nnz_feat
 
     root.dfs(collect_stat)
 
     # 16 is because when storing sparse matrices, indices (int64) require 8 bytes and floats require 8 bytes
-    return np.dot(num_nnz_feat, num_branches) * 16
+    return total_num_weights * 16
 
 
 def _train_node(y: sparse.csr_matrix, x: sparse.csr_matrix, options: str, node: Node):