Objective Questions
-------------------
.. A mininum of 8 questions here (along with answers)
1. ``matrix(A) * matrix(B)`` and ``array(A) * array(B)`` are the same.
a. True
#. False
Answer: False
2. ``matrix(A) * array(B)`` does,
a. Element wise multiplication.
#. Matrix multiplication.
#. Cannot multiply a matrix object and array object.
#. Depends on the shape of A and B, if compatible matrix
multiplication will be done, otherwise element wise
multiplication.
Answer: Matrix multiplication
3. A and B are two matrix objects. Element wise multiplication in
matrices are done by,
a. A * B
#. ``multiply(A, B)``
#. ``dot(A, B)``
#. ``element_multiply(A,B)``
Answer: multiply(A, B)
4. ``norm(A)`` method determines the,
a. Frobenius norm
#. Infinity norm
#. Induced norm
#. Schatten norm
Answer: Frobenius norm
5. ``eig(A)[1]`` and ``eigvals(A)`` are the same.
a. True
#. False
Answer: False
6. The code snippet will work without an error,
::
A = matrix([[1, 2, 3, 4], [5, 6, 7, 8]])
inv(A)
a. True
#. False
Answer: False
7. What is the output of the following code,
::
x = matrix([[1, 2, 3], ['a', 2, 'c']])
identity(x.shape)
a. Will create an identity matrix of shape (2, 3).
#. ``identity()`` function takes an integer as argument and a tuple
is passed.
#. Will return, matrix([[1,0,1],[0,1,0]])
#. Will return, matrix([[0,1,0],[0,1,0]])
Answer: ``identity()`` function takes an integer as argument and a
tuple is passed.
8. ``norm(A,ord='fro')`` is the same as ``norm(A)``
a. True
#. False
Answer: True
Larger Questions
----------------
.. A minimum of 2 questions here (along with answers)
1. Consider an array [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]. A fold and add
operation consist of two phases, a right fold and add and a left
fold and add.
Say in first fold and add, we take the right fold of the array and
add it to the left like,
[1+10, 2+9, 3+8, 4+7, 5+6, 6, 7, 8, 9, 10]
and it becomes
[11, 11, 11, 11, 11, 6, 7, 8, 9, 10]
and in the second fold and add, we take the left fold of the new
array and add it to the right and it becomes,
[11, 11, 11, 11, 11, 17, 18, 19, 20, 21].
What will be the array after 22 such operations starting with [1,
2, 3, 4, 5, 6, 7, 8, 9, 10]
2. Find the infinity norm and the determinant of the inverse of the
product of matrices A and B.
::
A = [[ 1, 2, 3, 4], B = [[16, 15, 14, 13],
[ 5, 6, 7, 8], [12, 11, 10, 9],
[ 9, 10, 11, 12], [ 8, 7, 6, 5],
[13, 14, 15, 16]] [ 4, 3, 2, 1]]