From 004ad7ce65eaec52eb17ce300a8a0cce66f13f47 Mon Sep 17 00:00:00 2001
From: Niklas Birk <niklas.birk@niklas-birk.de>
Date: Sat, 16 Mar 2024 14:14:36 +0100
Subject: [PATCH] Refactor matrix.py

---
 src/matrix.py | 60 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 35 insertions(+), 25 deletions(-)

diff --git a/src/matrix.py b/src/matrix.py
index afcc479..660b707 100644
--- a/src/matrix.py
+++ b/src/matrix.py
@@ -93,7 +93,7 @@ class Matrix:
     def __transpose_internal__(self):
         rows = self.__shape__[0]
         cols = self.__shape__[1]
-        transposed_data = [[0 for _ in range(rows)] for _ in range(cols)]
+        transposed_data = [([0] * rows) for _ in range(cols)]
         for i in range(rows):
             for j in range(cols):
                 transposed_data[j][i] = self.__data__[i][j]
@@ -194,9 +194,7 @@ class Matrix:
     def __mul_matrix_internal__(self, other):
         rows = self.__shape__[0]
         cols = other.__shape__[1]
-
-        new_data = [[0 for _ in range(rows)] for _ in range(cols)]
-
+        new_data = [([0] * rows) for _ in range(cols)]
         for i in range(rows):
             for k in range(cols):
                 new_data[i][k] = sum([self.__data__[i][j] * other.__data__[j][k] for j in range(self.__shape__[1])])
@@ -221,6 +219,33 @@ class Matrix:
     def __rmul__(self, other):
         return self * other
 
+    def __norm_frobenius__(self):
+        rows = self.__shape__[0]
+        cols = self.__shape__[1]
+        abs_sum = 0
+        for i in range(rows):
+            for j in range(cols):
+                abs_sum += abs(self.__data__[i][j]) ** 2
+        return math.sqrt(abs_sum)
+
+    def __norm_colsum__(self):
+        rows = self.__shape__[0]
+        cols = self.__shape__[1]
+        col_sums = [0] * cols
+        for j in range(cols):
+            for i in range(rows):
+                col_sums[j] += abs(self.__data__[i][j])
+        return max(col_sums)
+
+    def __norm_rowsum__(self):
+        rows = self.__shape__[0]
+        cols = self.__shape__[1]
+        row_sums = [0] * rows
+        for i in range(rows):
+            for j in range(cols):
+                row_sums[i] += abs(self.__data__[i][j])
+        return max(row_sums)
+
     def norm(self, f: str = "frobenius"):
         """
         Calculates the norm of the matrix.
@@ -228,33 +253,18 @@ class Matrix:
         A norm is a positive definit, absolute homogeneous and subadditive function.
         For Matrices a norm is also sub-multiplicative.
 
-        :param f: The norm to be used, could be either "frobenius", "rowsum" or "colsum"
+        :param f: The norm to be used, could be either "frobenius", "row sum" or "col sum"
 
         :return: the norm as a number
         """
-        norm = 0
-
-        rows = self.__shape__[0]
-        cols = self.__shape__[1]
-
         if f == "frobenius":
-            abs_sum = 0
-            for i in range(rows):
-                for j in range(cols):
-                    abs_sum += abs(self.__data__[i][j]) ** 2
-            norm = math.sqrt(abs_sum)
+            norm = self.__norm_frobenius__()
         elif f == "col sum":
-            row_sum = [0 for _ in range(cols)]
-            for j in range(cols):
-                for i in range(rows):
-                    row_sum[j] += abs(self.__data__[i][j])
-            norm = max(row_sum)
+            norm = self.__norm_colsum__()
         elif f == "row sum":
-            col_sum = [0 for _ in range(rows)]
-            for i in range(rows):
-                for j in range(cols):
-                    col_sum[i] += abs(self.__data__[i][j])
-            norm = max(col_sum)
+            norm = self.__norm_rowsum__()
+        else:
+            raise ValueError(f"Parameter f must be either \"frobenius\", \"row sum\" or \"col sum\"")
         return norm
 
     def __getitem__(self, key):