Error using a function in App Designer, not returning the correct value.

I am attempting to create an fsolve function inside of an app in the App Designer tool.

 methods (Access = private)
        
        function Deceleration = SolveForDecel(~,UTF,HB,HT,L,LB,LT,WC,WT,PHI,CHI,PSI,PSIT)
           fun = @(x) x*(1+PHI)*(1+WC/(WC+WT))/((1-PSI+x*CHI)-(WC/(WC-WT))*((1-PSIT)*LB/L+x*((HT/LT-HB/LT)*LB/L-HB/L)))-UTF;
           x = fzero(fun,.1);
           Deceleration = x;
        end
    end
    

    methods (Access = private)

        % Callback function: SolveforDecelerationButton, UIFigure
        function UIFigureKeyPress(app, event)

            valuefordecel = SolveForDecel(app,app.TireRoadfrictioncoefficientEditField.Value, ...
                            app.GroundhitchballEditField.Value, ...
                            app.GroundcgtrailerEditField.Value, ...
                            app.WheelbaseofcarEditField.Value, ...
                            app.RearaxlecarhitchballEditField.Value, ...
                            app.TraileraxlehitchballEditField.Value, ...
                            app.WeightofcarEditField.Value, ...
                            app.WeightoftrailerEditField.Value, ...
                            app.RearbrakeFtotalbrakeFEditField.Value, ...
                            app.cgheightcarwheelbaseEditField.Value, ...
                            app.rearaxlenotrailerweightEditField.Value, ...
                            app.rearaxletrailerweightEditField.Value);
           app.DecelerationofCombinationEditField.Value = valuefordecel;
                            

I believe the event is being triggered, and then it runs into an issue in the Fsolve (these are the outputs):

Exiting fzero: aborting search for an interval containing a sign change

because NaN or Inf function value encountered during search.

(Function value at -1.15052e+308 is NaN.)

Check function or try again with a different starting value.

Error using matlab.ui.control.internal.model.AbstractNumericComponent/set.Value (line 185)

'Value' must be a double scalar within the range of 'Limits'.

Error in Trailer_Dynamic_Simulation_Model/UIFigureKeyPress (line 79)

app.DecelerationofCombinationEditField.Value = valuefordecel;

Error using matlab.ui.control.internal.controller.ComponentController/executeUserCallback (line 335)

Error while evaluating Button PrivateButtonPushedFcn.

I am at a loss to determine exactly what the solution is. When I manually run through the function in the command window with realistic values it solves to .3014, which makes sense.

The error it is reading out in App Designer is:

[Cris LaPierre]

It would be easier to provide assistance if you share the app. Is that possible? If not, perhaps provide what realistic values for the inputs should be.

[George Fryda]

Of course. It won't let me attach the App file, it doesn't support .mlapps, but realistic values may be seen here:

In particular, these are the values that fed correctly into the function when i did it in the command vindow, and worked - giving x as [.3014].

(Chi needed to be CHI)

[Guillaume]

What are the values of the inputs that trigger the error?

Answer 1

[Jyotsna Talluri]

Hi,

The possible cause of error may be because of using 'Edit Field(Text)' instead of 'Edit Field (Numeric)'.Make sure you are using the 'Edit Field(Numeric)'.It worked for me when I reproduced it with your given inputs and equation as shown in the attched figure

[George Fryda]

Thank you for the suggestions Jyotsna,

I cannot find exactly where this would be in the code. In the place where the inputs are being declared appears to already specify that they are numeric.

% Create GroundcgtrailerEditField
            app.GroundcgtrailerEditField = uieditfield(app.UIFigure, 'numeric');
            app.GroundcgtrailerEditField.Limits = [0 Inf];
            app.GroundcgtrailerEditField.Position = [179 661 100 22];

Is there somewhere else?

[Jyotsna Talluri]

If you are declaring the inputs through the Numeric edit fields ,the it should work fine.Can you share the entire code in a .m file and the app layout screenshot so that I can check once?