from __future__ import division
from visual import *

"""

    Filename: YourName_Lab1_PHYS495_4.py

    Author: Your Name
    
    Date: 01/17/2007

    Description: Vector quantities in Python.

"""

"""
    A vector is declared with the 'vector' function,
    which takes three arguments.

    The first argument is the x-component; the second
    argument is the y-component; the third argument is
    the z-component.

    The following lines declare two vectors, named A
    and B.  Notice that vector A points only along the x-axis,
    since its y- and z-components are zero.

"""

A = vector(14.14, 0.0, 0.0) # vector pointing along the x-axis

B = vector(10.0, 10.0, 0.0) # vector pointing along x- and y-axes.

print "Vector A is ", A # don't use the format string!

print "Vector B is ", B # don't use the format string!

"""
    To access a particular component, use the
    dot-operator:

    A.x for the x-component of A
    A.y for the y-component of A
    A.z for the z-component of A

    DO use format strings for components of a vector, but
    not when printing the full vector.

"""

print "The x-component of A is %3.2f " %A.x

print "The x- and y-components of B are %3.2f and %3.2f " %(B.x,B.y)

"""
    To calculate the magnitude of a vector, use
    the mag() function.

    The following line declares the variable A_mag
    and stores the magnitude of the vector A.

    Then we do the same for B.

"""

A_mag = mag(A)

B_mag = mag(B)

print "The magnitude of vector A is %3.2f " %A_mag

print "The magnitude of vector B is %3.2f " %B_mag

"""
    To calculate the dot product of two vectors, use
    the dot() function.

"""

AB_dot = dot(A,B)

print "The dot product of vectors A and B is %3.2f " %AB_dot

"""
    To calculate the cross product of two vectors, use
    the cross() function.

    Notice that we DON'T use a format string to print
    AB_cross.  It's a vector quantity.

"""

AB_cross = cross(A,B)

print "The cross product of A and B is ", AB_cross

"""

    To add or subtract vectors, just use the + and -
    operators.

"""

AB_add = A + B

print "The sum of A and B is ",AB_add

AB_subtract = A - B

print "The difference of A and B is ", AB_subtract

"""

    It's easy to change the values of the components.
    Just use the dot operator as you did above.

"""

A.x = 3.0
A.y = 4.0
A.z = 5.0


print "Now, vector A is ", A

"""
    Create a new vector, using the name C.

    Write code to add vectors A and B and store the result
    in C.  Then, evaluate the magnitude of C, using a new
    variable name to store the result.

    Finally, use format strings to print the value of each
    component of C and its magnitude, using 3 decimal places.

"""