From 0322122c3819a812ca23309626774dd43c99f930 Mon Sep 17 00:00:00 2001
From: Ryan Dunn <71475179+RyanDunn729@users.noreply.github.com>
Date: Thu, 27 Apr 2023 14:56:02 -0700
Subject: [PATCH] Update systemgraph to use sparse zeros matrix

---
 python_csdl_backend/core/systemgraph.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/python_csdl_backend/core/systemgraph.py b/python_csdl_backend/core/systemgraph.py
index 7e8dcf5..9d753cb 100644
--- a/python_csdl_backend/core/systemgraph.py
+++ b/python_csdl_backend/core/systemgraph.py
@@ -812,7 +812,7 @@ def generate_reverse(self, output_ids, input_ids):
                 else:  # case 3:
                     rev_block.comment(f'{totals_name} = zero')
                     input_size = np.prod(self.unique_to_node[input_id].var.shape)
-                    prerev_vars[totals_name] = np.zeros((output_size, input_size))
+                    prerev_vars[totals_name] = sp.csc_matrix((output_size, input_size))
 
             # print statement
             print_loading(