Error Message: Output argument "I" (and maybe others) not assigned during call to "simpsons".

Hi, so I recently wrote a function

function I = simpsons(f,M,a,b)

h = (b-a)/(M-1);

f = @(x) x;

if rem(M,2) == 0

simpsons1(f,M,a,b)

elseif rem(M,3) == 0

simpsons2(f,M,a,b)

else

simpsons2(f,4,a,3*h) + simpsons1(f,M-3,3*h,b)

end

However, when I call the function in another script, I get the message Output argument "I" (and maybe others) not assigned during call to "simpsons".

This is my script

%i calculating pressure at a given depth

p0 = 101325;

g = 9.81;

for i = 1:1:43

I = 1;

I = simpsons(1,43,0,z(i));

pz = I;

pzm(i) = p0 + I*g;

end

Answer 1

[Stephen23]

Although you specified one output argument I:, nowhere in the code did you define I:

function I = simpsons(f,M,a,b)
...
I = ???? % you did not define I anywhere

Most likely you will want to return the simpsons2 ouputs:

function I = simpsons(f,M,a,b)
h = (b-a)/(M-1);
%f = @(x) x;
if rem(M,2) == 0
    I = simpsons1(f,M,a,b);
elseif rem(M,3) == 0
    I = simpsons2(f,M,a,b);
else
    I = simpsons2(f,4,a,3*h) + simpsons1(f,M-3,3*h,b);
end