Switch case error before to run simulation?

Question

Tony Castillo 2016-6-1

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链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/286832-switch-case-error-before-to-run-simulation

评论： Tony Castillo 2022-5-31

Hello can some one tell me why i get this mistake when i try to run the simulation?

Output argument 'battery' is not assigned on some execution paths.
Function 'MATLAB Function1' (#131.10.17), line 1, column 11:
"battery"
Launch diagnostic report.
function [battery, load, Emerg] = BattController1(SOC, Vconv)
%#codegen
persistent casevar
if isempty (casevar)
    casevar=0;
end
switch (casevar)
    %     case 0
    %         if SOC==0 casevar=0;
    %             battery=0;
    %             load=0;
    %             Emerg=0;
    %         end
    case 1
        if SOC>=95 casevar=1;
            load=1;
            battery=0;
            Emerg=0;
        end
        %suppliying load from batteries and disconnect it from PV panels charge in order to avoid overcharges
    case 2
        if (30<SOC) && (SOC<95) casevar=2;
            load=1;
            battery =1;
            Emerg=0;
        end
        %suppliying load from batteries and batteries charging
    case 3
        if (SOC<30) && (Vconv>19) casevar=3;
            load=0;
            battery=1;
            Emerg=1;
        else
            load=0;
            battery=0;
            Emerg=0;
        end
        %battery charging of PV panels and load disconected from batteries
    otherwise
        load=0;
        battery=0;
        Emerg=0;
end

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Walter Roberson 2022-5-31

在 MATLAB Online 中打开

    case 1
        if SOC>=95

if you got case 1 but SOC<95 then MATLAB will not look inside case 2 and the others to find matches, and will not activate the otherwise.

You should set the output values to the otherwise choices first, and then after that have your case that will fill in better values sometimes... and if not then the outputs will still be set to 0 or whatever you initialize

Tony Castillo 2022-5-31

@SALAH alatai It has been a while since I faced this issue, I can not find the file unfortunately.

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Answer 1

Walter Roberson 2016-6-1

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/286832-switch-case-error-before-to-run-simulation#answer_224147

Suppose case 1 but SOC < 95, then what will battery be assigned?

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Tony Castillo 2016-6-1

I suppose you mean this: if SOC>=95 casevar=1; I still don't know what is the error.

Stephen23 2016-6-2

编辑：Stephen23 2016-6-2

@Tony Castillo: read Walter's answer again: consider case 1 and SOC<95, then you do not define the outputs. But you call the function with some outputs, and yet they are not defined... thus the error.

The solution is to define the outputs for every possible permutation of states, or to define some default values once at the beginning of the function.

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