From dd1a7630b0e5477db0587586710b257159540ef2 Mon Sep 17 00:00:00 2001
From: ruxandravr <ruxandra.avram97@gmail.com>
Date: Sat, 20 Oct 2018 16:37:23 +0300
Subject: [PATCH 1/3] Add SST.py

---
 python/ad-hoc/SST.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 python/ad-hoc/SST.py

diff --git a/python/ad-hoc/SST.py b/python/ad-hoc/SST.py
new file mode 100644
index 0000000..25a5b08
--- /dev/null
+++ b/python/ad-hoc/SST.py
@@ -0,0 +1,20 @@
+import  numpy as np
+def SST(A, b):
+    # if the matrix is not upper triangular, we cannot solve the system
+    if np.allclose(A, np.triu(A)) == False:
+        print("The matrix A is not upper triangular!")
+        x = np.nan
+        return
+
+    n = len(b)
+    x = np.zeros((n, 1))
+
+    # calculate xn
+    x[n - 1, 0] = b[n - 1, 0] / A[n - 1, n - 1]
+
+    # calculate x(i) backwards
+    for i in range(n - 2, -1, -1):
+        sum_of_xs = np.dot(A[i, (i + 1) : n], x[(i + 1) : n, 0])
+        x[i, 0] = (b[i, 0] - sum_of_xs) / A[i, i]
+    
+    return x
\ No newline at end of file

From 0280d55b9affdf37d65217a65fda8a13175978c0 Mon Sep 17 00:00:00 2001
From: ruxandravr <ruxandra.avram97@gmail.com>
Date: Sat, 20 Oct 2018 17:03:16 +0300
Subject: [PATCH 2/3] Add SIT.py

---
 python/ad-hoc/SIT.py | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 python/ad-hoc/SIT.py

diff --git a/python/ad-hoc/SIT.py b/python/ad-hoc/SIT.py
new file mode 100644
index 0000000..e02d22c
--- /dev/null
+++ b/python/ad-hoc/SIT.py
@@ -0,0 +1,22 @@
+import  numpy as np
+def SIT(A, b):
+    # if the matrix is not lower triangular, we cannot solve the system
+    if np.allclose(A, np.tril(A)) == False:
+        print("The matrix A is not lower triangular!")
+        x = np.nan
+        return
+
+    n = len(b)
+    x = np.zeros((n, 1))
+
+    # calculate x1
+    x[0, 0] = b[0, 0] / A[0, 0]
+
+    # calculate x(i) forwards
+    for i in range (1, n):
+        sum_of_xs = np.dot(A[i, 0 : i], x[0 : i, 0])
+        x[i, 0] = (b[i, 0] - sum_of_xs) / A[i, i]
+    
+    return x
+
+print(SIT(np.tril(np.matrix([[1,2,3], [4,5,6], [7,8,9]])), np.array([[1], [14], [50]])))
\ No newline at end of file

From 2eb85d34cb3eebfdc07b336d13c86025305de2d5 Mon Sep 17 00:00:00 2001
From: ruxandravr <ruxandra.avram97@gmail.com>
Date: Sat, 20 Oct 2018 17:17:33 +0300
Subject: [PATCH 3/3] Refactor SIT.py

---
 python/ad-hoc/SIT.py | 29 +++++++++++++----------------
 python/ad-hoc/SST.py | 20 --------------------
 2 files changed, 13 insertions(+), 36 deletions(-)
 delete mode 100644 python/ad-hoc/SST.py

diff --git a/python/ad-hoc/SIT.py b/python/ad-hoc/SIT.py
index e02d22c..1faf8b4 100644
--- a/python/ad-hoc/SIT.py
+++ b/python/ad-hoc/SIT.py
@@ -1,22 +1,19 @@
 import  numpy as np
 def SIT(A, b):
-    # if the matrix is not lower triangular, we cannot solve the system
-    if np.allclose(A, np.tril(A)) == False:
-        print("The matrix A is not lower triangular!")
-        x = np.nan
-        return
+  # if the matrix is not lower triangular, we cannot solve the system
+  if not np.allclose(A, np.tril(A)):
+    print("The matrix A is not lower triangular!")
+    return np.nan
 
-    n = len(b)
-    x = np.zeros((n, 1))
+  n = len(b)
+  x = np.zeros((n, 1))
 
-    # calculate x1
-    x[0, 0] = b[0, 0] / A[0, 0]
+  # calculate x1
+  x[0, 0] = b[0, 0] / A[0, 0]
 
-    # calculate x(i) forwards
-    for i in range (1, n):
-        sum_of_xs = np.dot(A[i, 0 : i], x[0 : i, 0])
-        x[i, 0] = (b[i, 0] - sum_of_xs) / A[i, i]
+  # calculate x(i) forwards
+  for i in range (1, n):
+    sum_of_xs = np.dot(A[i, 0 : i], x[0 : i, 0])
+    x[i, 0] = (b[i, 0] - sum_of_xs) / A[i, i]
     
-    return x
-
-print(SIT(np.tril(np.matrix([[1,2,3], [4,5,6], [7,8,9]])), np.array([[1], [14], [50]])))
\ No newline at end of file
+  return x
\ No newline at end of file
diff --git a/python/ad-hoc/SST.py b/python/ad-hoc/SST.py
deleted file mode 100644
index 25a5b08..0000000
--- a/python/ad-hoc/SST.py
+++ /dev/null
@@ -1,20 +0,0 @@
-import  numpy as np
-def SST(A, b):
-    # if the matrix is not upper triangular, we cannot solve the system
-    if np.allclose(A, np.triu(A)) == False:
-        print("The matrix A is not upper triangular!")
-        x = np.nan
-        return
-
-    n = len(b)
-    x = np.zeros((n, 1))
-
-    # calculate xn
-    x[n - 1, 0] = b[n - 1, 0] / A[n - 1, n - 1]
-
-    # calculate x(i) backwards
-    for i in range(n - 2, -1, -1):
-        sum_of_xs = np.dot(A[i, (i + 1) : n], x[(i + 1) : n, 0])
-        x[i, 0] = (b[i, 0] - sum_of_xs) / A[i, i]
-    
-    return x
\ No newline at end of file