Finding Definitess of a Matrix

Hello guys. I'm quit beginner. I'm trying to ask a user to input a matrix. But the goal is I need to be able to find the definitess of the matrix that will be input. I want the option that my code will say it's positive definite, positive semi-definite,indefinite, negative definite or negative semi-definite. Could you guys tell me or show me what is missing or function I should use so I can have the other option as well.

m=input('Enter the number of row (under 5): ');
n=input('Enter the number of column (under 5): ');

if m == n
   disp('Good Size')
elseif m >= 5
    disp("to large square matrix");
elseif n >= 5
    disp("To large square matrix");
end

for i=1:m
    for j=1:n
        a(i,j)=input('enter the elements (each Number in row order): ');
    end
end
a = reshape(a,m,n)

try chol(a)
    disp("Matrix is symmetric positive definite")
catch ME
    disp('Matrix is not symmetric positive definite')
end

tf = issymmetric(a)
d = eig(a)
isposdef = all(d > tol)
issemidef = all(d > -tol)

Answer 1

[Matt J]

You alread have code that checks if a is postive (semi) definite. You can use that to see if -a is positive (semi) definite, which would imply that a is negative (semi) definite. If none of the above, you can conclude that it is indefinite.