Problem with if and than and det

So basically im trying script that determines if matrix is singular or not, by doing a det on the matrix. For example i tired doing: det([1 2;3 4]) which result in zero, but when I tired to input into the command like singularitytest([1 2;3 4]) or A=[1 2;3 4] its output is just the matrix. I am not sure which part i have gotten wrong, the If and else statements or the det? or my input command?

function result = singularitytest(A)
         if det(A) == 0
            c = 0;
         else
            c = 100;
end

[Stephen23]

Note that using the determinant is not a good way to check if a numeric matrix is singular. It works in abstract mathematics, but not for real-life numeric matrices. This has been discussed many times on this forum:

https://www.mathworks.com/matlabcentral/answers/389977-does-the-function-chol-correctly-indicates-that-a-matrix-is-positive-definite

https://www.mathworks.com/matlabcentral/answers/381548-using-matlab-s-det-why-does-this-3x3-matrix-s-determinant-not-zero

https://www.mathworks.com/matlabcentral/answers/131506-is-the-rank-function-reliable

etc. etc.

[bondpen]

Thanks! Both this and my result/variables mix up helps me.

Answer 1

[Walter Roberson]

You assign something to variable named c, which you then do not use.

Your function expects something to be assigned to result but you never assign to that.

[bondpen]

Thanks! Both this and cond command helps me.