Regular matrix and non-singular matrix

Hey

I need to write a function that the user enters a matrix, and the function returns "1" if the matrix is reversible(regular) and "0" if it's not.

I wrote this function-

function x=irr_mat(A)
if isequal(A,zeros(n))
    x=0;
else
   if size(A,1)==size(A,2)
    x=1;
else
    x=0;
   end
end
end

n is the array of the matrix.

and I got this note-

Error in irr_mat (line 3)
if isequal(A,zeros(n))

Error in Untitled5 (line 3)
irr_mat(A)

any help?

[Stephen23]

Where do you define n ?

[Noa Yelin]

I just find out that I didn't define n.

How can i define n that the user can put in matrix in which size he want to?

[Noa Yelin]

any help?

How can i define n that the user can put in matrix in which size he want to?

[Steven Lord]

You compute it from the input the user gave you using size.

[Noa Yelin]

n=size?

[Noa Yelin]

function x=irr_mat(A)
n=size
if isequal(A,zeros(n))
    x=0;
else
   if size(A,1)==size(A,2)
    x=1;
else
    x=0;
   end
end
end

it print me -

Error in irr_mat (line 3)
n=size

Error in Untitled5 (line 3)
irr_mat(A)

[Steven Lord]

size requires at least one input, the array whose size you're trying to compute. In this case you probably want to call it with two inputs. To see what that second input represents, I recommend reading or at least skimming the documentation page.

doc size

[Noa Yelin]

ok when i did this functionn -

function x=irr_mat(A)
n=size(A)
if isequal(A,zeros(n))
    x=0;
else
   if size(A,1)==size(A,2)
    x=1;
else
    x=0;
   end
end
end

and call the function -

A=randi([0,100],4);
irr_mat(A)

I don't get matrix.. i get always -

n =

     4     4


ans =

     1

[Francesco Tricarico]

You've said

"I need to write a function that the user enters a matrix, and the function returns "1" if the matrix is reversible(regular) and "0" if it's not."

It seems that you're last function version works well ("1" is the expected output).

[Noa Yelin]

yes, but when i wrote 4 here -

A=randi([0,100],4);
irr_mat(A)

i need to get matrix with 4X4.

[Rik]

A is 4x4, x is not.

[KSSV]

You asked the same question three times. There is no clarity in your question.

[Noa Yelin]

i dont get A 4X4. I got -

n =

4 4

ans =

1

I need to get matrix A with 4 rows and 4 columns

[Steven Lord]

What specifically do you mean by "reversible(regular)"? Which of the following count as reversible / regular and why do they count or not count?

A1 = 1
A2 = 42
A3 = 99
A4 = 12321
A5 = [1 2; 3 4]
A6 = [1 23; 23 1]
A7 = [98 89; 764 467]
A8 = [1 2 3 4; 5 6 7 8; 9 10 10 9; 8 7 6 5; 4 3 2 1]