Elizabeth - 2020-07-10T12:53:18+00:00
Question: "Runtime Error: Call to MATLAB function aborted: Domain error. To compute complex results, make at least one input complex, e.g. 'power(complex(a),b)'."
Hello, I'm trying to solve the following system in Simulink. I have some coder.extrinsic('intpolyval') into the Embeeded Matlab Function to deal with function handles I need to use while exchanging variables between functions, for instance: function sol=intpolyval(coeff,minx,maxx) sol=integral(@(x) polyval(coeff,x),minx,maxx); end While i try to run my model I get the error in debugger: "Runtime Error: Call to MATLAB function aborted: Domain error. To compute complex results, make at least one input complex, e.g. 'power(complex(a),b)'." This only happens when there is a loop in the Simulink model, while the model is simple- everything goes all right. Did anyone have similiar problems? How have u worked arround it?
Expert Answer
Prashant Kumar answered .
2025-11-20
When there is a expression that might produce a complex result, the input signals for the calculation must be changed to Complex, or you must use complex() on the real signals that might produce a complex result. For example if you have sqrt() then if the input might go negative then you need to complex() the input before taking the sqrt.
I gather the error shows up at the time the need for a complex result is detected, so if you are not expecting the calculation to produce a complex result you may need to add debugging to see why it does produce such a result.
MATLAB silently transforms values to complex at need, but Simulink does not.
When you have a loop, Simulink has to solve the loop to establish the initial conditions for self-consistency because everything in one step has to be true simultaneously (if that is not needed for you then send your signal through a time delay so the rest of the calculation can be performed in the next step) . The result can include values outside the range you expect.
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