Output argument "name of variable" (and possibly others) not assigned a value in the execution with "function name" function. Can someone explain what this means?

I am calling a function from the command line but it does not save the output and return it like it is supposed to. rather it gives me this error "Output argument "name of variable" (and possibly others) not assigned a value in the execution with "function name" function. "

[Stephen23]

You did not define the output variable. For example, output C is not defined anywhere in the function:

out = myfun(pi)

Output argument "C" (and possibly others) not assigned a value in the execution with "solution>myfun" function.

function C = myfun(x)
A = sqrt(x);
B = acos(x);
end

Answer 1

[Steven Lord]

Another common cause of this error is that the function contains at least one code path on which the output variable is defined and at least one on which it is not. In the example below y is defined if x is greater than 0 or if x is less than 0. It's not defined if x is exactly 0.

result1 = example1717445(1)

result1 = 2

resultm1 = example1717445(-1)

resultm1 = 2

result0 = example1717445(0)

Output argument "y" (and possibly others) not assigned a value in the execution with "solution>example1717445" function.

function y = example1717445(x)
% y = NaN;
if x > 0
    y = 2*x;
elseif x < 0
    y = -2*x;    
end
end

One way to detect or avoid this is to unconditionally assign a value to that output at the top of the function. Make a copy of the example code and uncomment the line that assigns NaN to y and that third call will no longer error, as there's no longer a code path that doesn't define y.