Homework, Material, and Software Manual for Math 4610
Routine Name: crossprod
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 take the cross product of two vectors of length 3. It will perform xxy.
Input: The inputs for this method need to be two vectors of length 3. The first input will be x and the second will be y.
Output: This will return the cross product vector of the two vectors.
Usage/Example:
First let’s create two vectors c and d of size 3 and set each element to a specific number.
c = [float(0) for i in range(0, 3)]
d = [float(0) for i in range(0, 3)]
c[0] = 1.5
c[1] = 9.4
c[2] = 3.3
d[0] = 1
d[1] = 9
d[2] = 3
Now let’s print out the value return from our function given our created vectors.
print(crossprod(c, d))
This will print
[-1.4999999999999964, -1.2000000000000002, 4.1]
to the console. Doing
crossprod(d,c)
will give
[1.4999999999999964, 1.2000000000000002, -4.1]
Implementation/Code: The following is the code for crossprod(x, y)
def crossprod(x,y):
if len(x) != 3 and len(x) != 3:
return "Error Vector is not in R3."
newVector = [0 for i in range(0, len(x))]
newVector[0] = (x[1]*y[2]) - (x[2]*y[1])
newVector[1] = (x[2]*y[0]) - (x[0]*y[2])
newVector[2] = (x[0]*y[1]) - (x[1]*y[0])
return newVector
Last Modified: December 2018