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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
on 26 Dec 2019

Roshni Garnayak
on 8 Jan 2020

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:

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