What is the error in my function? Error: Variable 'T' is not fully defined on some execution paths.

This is the code which I wrote for generating a Trapezoid curve for BLDC motor. It is showing the following error: 'Variable 'T' is not fully defined on some execution paths'. The code:

    % code
function y = fcn(u)
%#codegen
Q = mod(u,2*pi);
if Q >=0 && Q<2*pi/3    
T = 1;
elseif Q>= 2*pi/3 && Q< pi
    T = 1-6*(Q-2*pi/3)/pi;
elseif Q>= pi && Q<5*pi/3
    T = -1;
elseif Q>= 5*pi/3 && Q<2*pi
    T = -1 + 6*(Q-5*pi/3)/pi;
end
y=T;

Answer 1

[Walter Roberson]

None of the branches is encountered if u is infinite or nan.

function y = fcn(u)
%#codegen
Q = mod(u,2*pi);
if Q<2*pi/3    
    T = 1;
elseif Q < pi
    T = 1-6*(Q-2*pi/3)/pi;
elseif Q < 5*pi/3
    T = -1;
elseif Q < 2*pi
    T = -1 + 6*(Q-5*pi/3)/pi;
else
    T = nan;   %if data was inf or nan
end
y=T;

[Stephen23]

@Walter Roberson: I changed the last elseif to else, that seemed to be the intention.

[Walter Roberson]

I am not convinced that is an appropriate output if the input is nan or inf.

[Stephen23]

??? I apologize if that was not the intention. Surely an else will give an output, which resolves the original question.

[Meghdeep Jana]

Thank you for the solution. It is working fine now.

[Walter Roberson]

Sorry, Stephen, I mis-read what you were saying.

[Alejandro Zavala]

I want to run this code

  function D=inc(V,I)
Dinit=.574;
deltaD=0.001;
persistent Va  Da Ia;
if isempty(Da)
  Va=42.64;
  Ia=2;
  Da=Dinit;
end
dV=V-Va;
dI=I-Ia;
if dV== 0
  if dI==0 
  else
      if dI>0
          D=Da-deltaD;
      else
          D=Da+deltaD;
      end
  end
else
  if dI/dV==-I/V
  else
      if dI/dV>-I/V
      D=Da-deltaD;
      else
      D=Da+deltaD;
      end
  end
end
Da=D;
Va=V;
Ia=I;
but Matlab shows this error
Variable 'D' is not fully defined on some execution paths.

[小东 刘]

hello! I have the same problem now.may I ask how you solved it later ?