From 881e6d1fd7951009ebaa0b9c2dc062b5eea53e89 Mon Sep 17 00:00:00 2001
From: thisisapple <85461103+thisisapple@users.noreply.github.com>
Date: Sun, 1 Sep 2024 20:56:56 -0500
Subject: [PATCH] Update assembly.py

When the user adds a node, the original element will be deleted. The SystemElements object cannot pass validation because a non-existing element was referenced. An error will occur.
To avoid this error, I use the enumerate() method.
---
 anastruct/fem/system_components/assembly.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/anastruct/fem/system_components/assembly.py b/anastruct/fem/system_components/assembly.py
index 7cf830ec..e4cc38d0 100644
--- a/anastruct/fem/system_components/assembly.py
+++ b/anastruct/fem/system_components/assembly.py
@@ -223,8 +223,8 @@ def assemble_system_matrix(
     #
     # thus with appending numbers in the system matrix: column = row
 
-    for i in range(len(system.element_map)):
-        element = system.element_map[i + 1]
+    i, element in enumerate(system.element_map.values()):
+        # element = system.element_map[i + 1]
         element_matrix = element.stiffness_matrix
 
         # n1 and n2 are starting indexes of the rows and the columns for node 1 and node 2