Activity 2

Download Octave for Windows

GNU Octave is similar to Matlab, supports linear algebra

1. Define a 1x3 matrix.

   octave:112> a=[1,2,3]
   a =
   1 2 3

    

2. Define a 3x1 matrix.

   octave:113> b=[4;5;6]
   b =
   4
   5
   6
    

3. Add

   octave:116> b+b
   ans =
   8
   10
   12
    

4. Scalar Multiplication

   octave:117> 3*a
   ans =
   3 6 9
    

5. Matrix Multiplication

   octave:114> a*b
   ans = 32

   octave:119> A=[1,2,4;2,6,0]
   A =
   1 2 4
   2 6 0
   
   octave:120> B=[4,1,4,3;0,-1,3,1;2,7,5,2]
   B =
   4 1 4 3
   0 -1 3 1
   2 7 5 2
   
   octave:121> A*B
   ans =
   12 27 30 13
   8   -4 26 12

   B*A is not defined
    

6. Identity

   octave:134> eye(3,3)
   ans =
   1 0 0
   0 1 0
   0 0 1
   
   octave:137> C=[1,2,0;0,1,1;0,0,1]
   C =
   1 2 0
   0 1 1
   0 0 1

   octave:139> C*eye(3,3)
   ans =
   1 2 0
   0 1 1
   0 0 1
    

7. Transpose

   octave:140> C.'
   ans =
   1 0 0
   2 1 0
   0 1 1
    

8. Inverse

   octave:141> inverse(C)
   ans =
   1 -2 2
   0 1 -1
   0 0 1
    

9. Dot product

   octave:142> u=[1;2;3]
   u =
   1
   2
   3
   
   octave:143> v=[0;1;0]
   v =
   0
   1
   0
   
   octave:144> dot(u,v)
   ans = 2
    

10. Cross product

    octave:145> cross(u,v)
    ans =
    
    -3
    0
    1