why is it takes so much to calculate this function ?

hi I have this code that describes soltion of ODE . I am using Euler method for solveing first order first degree of ODE .

the problem is that for some reason ,this function takes a lot of time . and when I am ploting the resluts . it gets stuck why is that ?

 %%% values for calcalution of I1_desire 
U=values_of_circuit.U; %% Vin
R=values_of_circuit.R; %% Rload 

 C2=values_of_circuit.C2; %% Capacitance of the output capsitor 
 C1=values_of_circuit.C1; %% Capacitance of the first capsitor 
 L1=values_of_circuit.L1; %% Inductnce of inductor 1 
 L2=values_of_circuit.L2; %% Inductnce of inductor 2

 R_C2=values_of_circuit.R_C2; %% Resistence of the C2
  R_C1=values_of_circuit.R_C1; %% Resistence of the C1 
 
 
 R1=values_of_circuit.R1;   %% Resistence of the L1 (also this parmater is used for the half idial simulation )
 R2=values_of_circuit.R2;   %% Resistence of the L2
  
 R_diode=values_of_circuit.R_diode; %% Resistence of diode 
 V_diode=values_of_circuit.V_diode; %% Forward volatge across the  diode 
 
 alpha_1=Duty_Cycle_Parmeters.alpha_desire; %% alpha desire for the desried output voltage
 t_ode=Run_Time_Values.t_ode;  %% end time of the running simulation 
   
 
 
 A_a=Basic_Matrix.A_a;
 A_b=Basic_Matrix.A_b;
 B_a=Basic_Matrix.B_a;
 B_b=Basic_Matrix.B_b;
 C_a=Basic_Matrix.C_a;
 C_b=Basic_Matrix.C_b;

 

                I_1_desired=0.56187;
%                I_1_desired=x_t_symbolic(3);
              I_1_desired=double(subs(I_1_desired));
               Rohav_H=1; %% width of Histers window 
%                I1_desired_min=(I_1_desired)-(Rohav_H/2);
%                I1_desired_max=(I_1_desired)+(Rohav_H/2); 
                I1_desired_min=I_1_desired-0;
                I1_desired_max=I_1_desired+0;
              t_run_B_C=t_ode; %% run time for the function 
              t_delta_B_C=1000e-9; %% step size of the euler's therom 
              number_of_samples_B_C=round(t_run_B_C/t_delta_B_C); %%calculation of number of samples 
              S_switch=zeros(1,number_of_samples_B_C);%%S_switch= array of zeros with size of number_of_samples_B_C
              x=zeros(4,number_of_samples_B_C); %%x=array of zeros with size of number_of_samples_B_C
              x(:,1)=[ 0 0 0 0]';%% starting condtion 
              V_out_Boundery_Control=zeros(1,number_of_samples_B_C); %%V_out_Boundery_Control=array of zeros with size of number_of_samples_B_C
              j=0;   
              num_of_samples_for_1_delay=round((1/ 892e3)/t_delta_B_C);
              S_switch=zeros(1,round(number_of_samples_B_C/num_of_samples_for_1_delay));
              test_counter=zeros(1,round(number_of_samples_B_C/num_of_samples_for_1_delay));
              
 for i=1:number_of_samples_B_C-1
    if(rem(i,num_of_samples_for_1_delay)==0)
        
     j=j+1;
                     test_counter(j)=1;

       if (x(3,j)<=I1_desired_min)
            Switch_State=1;
        elseif(x(3,j)>I1_desired_max)
                Switch_State=0;
       else
    end
       
 
           S_switch(j)= Switch_State;
     
                A_total=A_a* Switch_State+A_b* not(Switch_State);
               B_total=B_a* Switch_State+B_b*not(Switch_State); 
                 C_total=C_a* Switch_State+C_b*not(Switch_State);
                x(:,i+1)=x(:,i)+t_delta_B_C*( A_total*x(:,i)+B_total*U); 
                S_switch(i+1)=0.5;
                V_out_Boundery_Control(:,i+1)=C_total*x(:,i+1);
                
                
               

         
    end
    
        

   
       t_testing=linspace(0,t_run_B_C, number_of_samples_B_C);
               size_t=size(t_testing);
               size_x=size(x);


        B_C_with_delay_Eulers_Results.x_BC_with_delay=x;
        B_C_with_delay_Eulers_Results.t_with_delay=t_testing;
         B_C_with_delay_Eulers_Results.V_R_BC_with_delay=V_out_Boundery_Control;
        B_C_with_delay_Eulers_Results.Switch_BC_with_delay=S_switch;
           B_C_with_delay_Eulers_Results.test=test_counter;

and if I plot the resluts ,the plot takes a lot of time to be ready , and also works very slow when I want to zoom in .

plot(B_C_with_delay_Eulers_Results.t_with_delay,B_C_with_delay_Eulers_Results.x_BC_with_delay(3,:),'-- red d');
  hold on;
  plot(B_C_with_delay_Eulers_Results.t_with_delay,0.5*B_C_with_delay_Eulers_Results.Switch_BC_with_delay,'-- blue d');
     hold on;  
     plot(B_C_with_delay_Eulers_Results.t_with_delay,0.5*B_C_with_delay_Eulers_Results.test,'-- magenta d');
     hold on;
    plot(B_C_with_delay_Eulers_Results.t_with_delay,1*I_1_desired*ones(size(B_C_with_delay_Eulers_Results.t_with_delay)),' black ','linewidth',3);  %% plot--> of boundery limit
    legend('I_1','Switch with delay ','test of the delay','boundery limit ');

[John D'Errico]

There is a reason why they only teach Euler's method to beginning students, but never recommend it as a method for later use. As methods go, it is usually crapola.

Answer 1

[Roshni Garnayak]

You can use the MATLAB Profiler to check which part of the code is consuming more time to run. Once you figure that out, you can optimize that part of the code.

To know more about the MATLAB Profiler, refer to the following link:

https://www.mathworks.com/help/matlab/ref/profile.html