angle and abs function gives me 'Subscript indices must either be real positive integers or logicals.' error

if strcmp(app.Type_of_analysis.Value,'Exact') && app.Primary.Value == 1

R2_= app.R2.Value*(app.Turns_ratio.Value)^2;

X2_double=str2double (app.X2.Value);

X1_double=str2double(app.X1.Value);

Xm_double=str2double(app.Xm.Value);

X2_=X2_double*(app.Turns_ratio.Value)^2;

V2_=app.Load_voltage.Value*(app.Turns_ratio.Value)^2;

angle= -acosd(app.Power_factor.Value);

Power1= app.Input_Power.Value*app.Percentage_of_loading.Value*0.01;

I_load_magnitude=Power1/V2_;

I_load_= I_load_magnitude*cos(angle*pi/180)+I_load_magnitude*sin(angle*pi/180)*1i;

V_x= V2_+I_load_*(R2_+X2_double);

I_m= V_x/Xm_double;

I_c= V_x/app.Rc.Value;

I_phi= I_m+I_c;

I_input= I_phi+I_load_;

I_input_angle= angle(I_input); ****Error*****

I_input_magnitude= abs(I_input); ****Error*****

Input_voltage= V_x+I_input*(app.R1+X1_double);

app.Input_voltage_magnitude= abs(Input_voltage);

app.Input_voltage_angle= angle(Input_voltage);

Power_factor1= cos(angle(Input_voltage)-I_input_angle);

app.Input_Power.Value=app.Input_voltage_magnitude*I_input_magnitude*Power_factor1;

app.Voltage_regulation.Value=(app.Input_voltage_magnitude-V2_)/V2_*100;

end

Answer 1

[Star Strider]

First the code defines:

angle= -acosd(app.Power_factor.Value);

then later it calls the angle function:

I_input_angle= angle(I_input); ****Error*****

and MATLAB now firmly believes that angle is a variable and not a function because that is what you told it earlier.

The solution is to re-name the ‘angle’ variable to something that does not overshadow the angle function and means something in context, for example ‘pf_angle’.

I do not see that anything is assigned to a variable ‘abs’, however I suspect something similar was done somewhere else in the code. The solution is similar.

.

Answer 2

[Voss]

Do you have a variable called abs? To find out, do:

whos abs

If there is one, clear it by doing:

clear abs

This will clear the variable abs from your workspace, allowing you to run the function abs.

[youssef Mostafa]

The error appears in the angle and abs function. and I tried ur solution but I didn't find a variable named abs

[John D'Errico]

@youssef Mostafa

You don't understand. This error essentially indicates you have done exactly that. For example, we see this line of code:

angle= -acosd(app.Power_factor.Value);

So you did create a variable named angle. Then you try to use the function angle.

I_input_angle= angle(I_input);              ****Error*****

However, this fragment of code is only part of what you have written. Somewhere in that code, you have defined a variable named abs.

DON'T DO THAT!