From 8354c38a8d387fb099c771e73595aafa1311e64a Mon Sep 17 00:00:00 2001
From: cjc13016 <31663413+cjc13016@users.noreply.github.com>
Date: Sun, 10 Dec 2017 19:42:41 -0500
Subject: [PATCH] SE_diff (Chris)

---
 SE_diff.m | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 SE_diff.m

diff --git a/SE_diff.m b/SE_diff.m
new file mode 100644
index 0000000..cbf4968
--- /dev/null
+++ b/SE_diff.m
@@ -0,0 +1,91 @@
+function [pw_se,w]=SE_diff(T,P,n)
+w = membrane_solution31(T,P,n);
+A = zeros(n,n);
+h = zeros(n,1);
+m = n+1; %Represents the number of nodes
+
+%Top Left Corner Interior Node
+for i = 2+m
+    A(i,i)=1;
+    A(i,i-1)=0;
+    A(i,i+m)=1;
+    A(i,i+m-1)=0;
+    h(i) = 10;
+end
+%Top Right Corner Interior Node
+for i = m*2-1
+    A(i,i)=1;
+    A(i,i-1)=1;
+    A(i,i+m)=1;
+    A(i,i+m-1)=1;
+    h(i) = 10;
+end
+%Bottom Left Corner Interior Node
+for i = m*m-(2*m)+1
+    A(i,i)=1;
+    A(i,i-1)=0;
+    A(i,i+m)=0;
+    A(i,i+m-1)=0;
+    h(i) = 10;
+end
+%Bottom Right Corner Interior Node
+for i = (m*m)-m-1
+    A(i,i)=1;
+    A(i,i-1)=1;
+    A(i,i+m)=0;
+    A(i,i+m-1)=0;
+    h(i) = 10;
+end 
+
+%The following represent the values for the interior nodes
+
+%Top Interior Row
+for i = 3+m:m*2-2
+    A(i,i)=1;
+    A(i,i-1)=1;
+    A(i,i+m)=1;
+    A(i,i+m-1)=1;
+    h(i) = 10;
+end
+%Bottom Interior Row
+for i = m*m-(2*m)+2:(m*m)-m-2
+    A(i,i)=1;
+    A(i,i-1)=1;
+    A(i,i+m)=0;
+    A(i,i+m-1)=0;
+    h(i) = 10;
+end
+%Left Interior Column
+for i = (2*m)+2,(2*m)+2:(m*m)-(2*m)+2
+    A(i,i)=1;
+    A(i,i-1)=0;
+    A(i,i+m)=1;
+    A(i,i+m-1)=0; 
+    h(i) = 10;
+end
+%Right Interior Column
+for i = (3*m)-1,(2*m)+2:(m*m)-(2*m)+2
+    A(i,i)=1;
+    A(i,i-1)=1;
+    A(i,i+m)=1;
+    A(i,i+m-1)=1;
+    h(i) = 10;
+end
+%Inerior Nodes
+for i = (2*m)+3:(3*m)-2,(2*m)+3:(m*m)-(3*m)+3
+    A(i,i)=1;
+    A(i,i-1)=1;
+    A(i,i+m)=1;
+    A(i,i+m-1)=1;
+    h(i) = 10;
+end
+
+
+dw_dx = (A(i,i)-A(i-1)+A(i,i+m)-A(i,i+m-1))/(2.*h);
+dw_dx'
+
+end 
+    
+    
+    
+    
\ No newline at end of file