Homework, Material, and Software Manual for Math 4610
Routine Name: trace
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 will find the trace of a given square matrix.
Input: This method takes one two dimensional array of dimensions nxn as its only input.
Output: This method will return the trace of the array which is a double value.
Usage/Example:
First let’s create a matrix a whose dimensions are 3x3 and set its values. If the array doesn’t have square dimensions then it will return an error message.
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]]
Let’s print the return value of our method.
print(trace(a))
This will print
7.0
to the console.
Implementation/Code: The following is the code for trace(x)
def trace(x):
if len(x) != len(x[1]):
return "Error Invalid sizes!"
tmpVal = 0.0
for i in range(0, len(x)):
tmpVal = tmpVal + x[i][i]
return tmpVal
Last Modified: December 2018