Homework, Material, and Software Manual for Math 4610
Routine Name: m1norm
Author: Tanner Wheeler
Language: Python. This code can be run on a python 3 compiler. The file can be imported and then the method will run.
Description/Purpose: This method will compute the l_1 Matrix Norm given a specific matrix.
Input: This method has only one input. This input x is a matrix of dimensions mxn.
Output: This method will return a double value representing the norm.
Usage/Example:
First create a matrix a with dimensions mxn and specify values for it.
n = 3
m = 3
a = [[float(0)] * n for i in range(0,m)]
a[0][0] = float(1)
a[0][1] = float(8)
a[0][2] = float(2)
a[1][0] = float(4)
a[1][1] = float(4)
a[1][2] = float(1)
a[2][0] = float(5)
a[2][1] = float(6)
a[2][2] = float(2)
Now we have
a = [[1.0, 8.0, 2.0],
[4.0, 4.0, 1.0],
[5.0, 6.0, 2.0]]
Now let’s print the output of our function given the matrix a.
print(m1norm(a))
This will print
18.0
to the console.
Implementation/Code: The following is the code for m1norm(x)
def m1norm(x):
tempVal = 0.0
newSum = 0.0
for j in range(0, len(x[1])):
for i in range(0, len(x)):
tempVal = tempVal + abs(x[i][j])
if tempVal > newSum:
newSum = tempVal
tempVal = 0.0
return newSum
Last Modified: December 2018