inv(W) problem

I got 2 problems:

1 is inv(W) i don't get why i matlab gives me this all the time

"Error using inv
Matrix must be square.

Error in laborki1 (line 39)
inv(W)

"

2. I am suppous to make W take as low place in computer memory as it is possible and I'm not sure if I did it well. If someone could explain me how does it work it would be grate.

So here i my script:

    clc

    disp('Daniel Siwiec')

    disp('Polecenie 1')

    A=[1,2,3;4,5,6;7,8,9]

    B=[2,3,4;5,6,7;8,9,10]

    A.*B

    B.*A

    A./B

    B./A

    disp('Polecenie 2')

    W=[1,3,5,7,9,11]

    W=[1:2:11]

    y=int8(W)

    x=input('Podaj liczbe X przez ktora zostanie przemnozony wektor W:')

    x*W

    disp('Polecenie 3')

    size (A)

    length (A)

    max (A)

    min (A)

    sum (A)

    inv (A)

    size (W)

    length (W)

    max (W)

    min (W)

    sum (W)

    inv(W)

[Jan]

Please format your code properly in the forum using the "{} Code" button. Use one command per line.

I do not understand this:

 I am suppous to make W take as low place in computer memory
 as it is possible.

[Daniel Siwiec]

Yea, I'm new in computer programing and Im not to familiar with computer vocabulary.

Lets say that W takes 64 bits in computer memory is there any way to make it samller? I tried to make it like this but i got no idea how to check if its ok.

y=int8(W)

[Jan]

See [EDITED] in my answer.

Answer 1

[Jan]

Only square matrices can be converted, as teh error message explains clearly. Inverting non-suqare matrices is not defined mathematically. Therefore it is not possible to guess, what you want to achieve.

[EDITED] The int8 command converts the input to signed 8 bit integers. The whos command shows, that this uses less memory. But note, that inv is not supported for integer types. So perhaps you search for single precision, which uses 4 bytes per value.