Note that according to standard definitions minus zero has the same value as positive zero: "...regarded as equal by the numerical comparison operations". This means they cannot be sorted (which by definition requires a value comparison function to provide the order):
>> -0<0
ans =
0
So sort will not work for you:
>> [out,idx] = sort([0,-0])
out =
0 0
idx =
1 2
If you want to sort them separately you will need to implement your own sort algorithm. The most reliable way to test for minus zero is to use a divide-by-zero and check the Inf sign:
>> 1./[-0,0]
ans =
-Inf Inf
Note that negative zero is not displayed in MATLAB:
>> x = 1*(-0)
x =
0
>> 1/x
ans =
-Inf
Interestingly the sort example above keeps the negative zero in the output:
>> 1./out
ans =
Inf -Inf
