Calling multiple .m files into separate function

function [B, H] = IsStable(polynomial)
if polynomial ~= AllNonZero(polynomial(false))
    B=0;
    H=[];
elseif polynomial ~= AllSameSign(polynomial(false))
    B=0;
    H=[];
else 
    H=HurwitzMatrix(polynomial);
    pm = length(H);                       
        for i=1:pm
        minor(i)=det(polynomial(1:i,1:i));             
        end
            if minor(i)>0
                B=1;    
            else
                B=0;
            end
end

I am trying to calculate the stability of a Hurwitz Matrix by checking if the principle minors are more than zero. Any sugestions to improve the above code as it is not working when I call three separate .m files e.g. AllNonZero, AllSameSign and HurwitzMatrix? Thank you.

[Walter Roberson]

What are you passing in as the first parameter? If you are not passing in an object or function handle, then polynomial(false) is a logical indexing request to return none of the elements of polynomial so polynomial(false) is likely to be empty.

[Mughees Asif]

The aim is to enter a row vector into the function, which, will cross check with the other three .m files before displaying 1 if the principle minors are more than zero and 0 if the principle minors are less than 0. When the row vector is entered into the function, it should check if all the signs are same, if any number is 0 and display the associated Hurwitz matrix. But for this file, I need it to check and display all three results from the files and then check for the principle minors.

[Mughees Asif]

function IsStable(polynomial)
if AllNonZero(polynomial) == false
    H=[]
elseif AllSameSign(polynomial) == false
    H=[]
else 
   HurwitzMatrix(polynomial);
   pm = length(polynomial);                       
        for i=1:pm
        minor(i)=det(polynomial(1:i,1:i));             
        end
            if minor(i)>0
                B=1  
            else
                B=0
            end
end

I tried changing the parameter but i get the error,

Index in position 1 exceeds array bounds (must not exceed 1).

Error in IsStable (line 10)
        minor(i)=det(polynomial(1:i,1:i));
 

[Adam]

You should presize your array before the for loop:

minor = zeros(1,pm);

[Mughees Asif]

function IsStable(polynomial)
if AllNonZero(polynomial) == false
    H = [];
elseif AllSameSign(polynomial) == false
    H = [];
else 
   HurwitzMatrix(polynomial);
   pm = length(polynomial);
   minor = zeros(1,pm);
   for i = 1:pm
     minor(i) = det(polynomial(1:i,1:i));             
     if minor(i) > 0
       B(i) = 1
     else
       B(i) = 0
     end
   end
end

I am still getting the same error,

Index in position 1 exceeds array bounds (must not exceed 1).

Error in IsStable (line 11)
     minor(i) = det(polynomial(1:i,1:i));

[Adam]

So, as Walter asked, what are you passing in as the parameter?

[Walter Roberson]

If AllNonZero is false then isn't the matrix all 0 or at least a row of 0?