How to resolve "Out of memory" error?? please look into the following code

clear all
clc
tspan = [0 2];
y01 = 0.1*ones(36,1);
y0 =[10 2.5 0 1 0.00025 0 0 0 0 (11.4*380/10000) -(5.5*380/10000) 380.8/380 0 (11.4*380/10000) (0.4*380/10000)...
    10 2.5 (1.9e-3) 1 1 0 0 0 0 (11.4*380/10000) -(5.5*380/10000) 380.8/380 0 (11.4*380/10000) (0.4*380/10000)...
    3.8*380/1000 0.4*380/10000 7.6*380/10000 1.6*380/10000 22.8*380/10000 0.8*380/10000];  
options = odeset('RelTol',1e-4,'AbsTol',1e-6);
[t, y] = ode23tb(@sysMG2, tspan, y01, options);
save MGinitialcond.mat

function dydt = sysMG2(t, y)
 i_dc1=y(1); v_dc1=y(2);delta1=y(3); P1=y(4); Q1=y(5); phi_d1=y(6); phi_q1=y(7); gamma_d1=y(8); gamma_q1=y(9);i_ld1=y(10);...
 i_lq1=y(11); vo_d1=y(12); vo_q1=y(13); io_d1=y(14); io_q1=y(15);
 i_dc2=y(16); v_dc2=y(17);delta2=y(18); P2=y(19); Q2=y(20); phi_d2=y(21); phi_q2=y(22); gamma_d2=y(23); gamma_q2=y(24);i_ld2=y(25); i_lq2=y(26); vo_d2=y(27); vo_q2=y(28); io_d2=y(29); io_q2=y(30); 
 i_lineD1=y(31);i_lineQ1=y(32);i_lineD2=y(33);i_lineQ2=y(34);
 i_loadD1=y(35);i_loadQ1=y(36);

 di_dc1dt=8790923519632281/8796093022208 - (9001905684103455*v_dc1)/9007199254740992 - (7201524547282765*i_dc1)/144115188075855872;
 dv_dc1dt=(900970629561481*i_dc1)/4503599627370496 - (562949953421312*P1)/(2813966534836365*v_dc1);
 ddelta1dt=200*pi;
 dP1dt=(3141*io_d1*vo_d1)/100 - (3141*P1)/100 + (3141*io_q1*vo_q1)/100;
 dQ1dt=(3141*io_q1*vo_d1)/100 - (3141*io_d1*vo_q1)/100 - (3141*Q1)/100;
 dphi_d1dt=380 - vo_d1 - (13*Q1)/10000;
 dphi_q1dt=-vo_q1;
 dgamma_d1dt=(3*io_d1)/4 - i_ld1 - (4796153459164483*Q1)/73786976294838206464 + 390*phi_d1 - vo_d1/20 - (pi*vo_q1)/200 + 19;
 dgamma_q1dt=(3*io_q1)/4 - i_lq1 + 390*phi_q1 - vo_q1/20 + (pi*vo_d1)/200;
 di_ld1dt=(13300*v_dc1)/81 - vo_d1*((35*v_dc1)/81 + 20000/27) - (91*Q1*v_dc1)/162000 + (3200000*gamma_d1*v_dc1)/243 + (175*io_d1*v_dc1)/27 + (91000*phi_d1*v_dc1)/27 - i_lq1*((pi*v_dc1)/9 - 31367/100) - i_ld1*((700*v_dc1)/81 + 2000/27) - (7*pi*v_dc1*vo_q1)/162;
 di_lq1dt=(3200000*gamma_q1*v_dc1)/243 - vo_q1*((35*v_dc1)/81 + 20000/27) + (175*io_q1*v_dc1)/27 + (91000*phi_q1*v_dc1)/27 + i_ld1*((pi*v_dc1)/9 - 31367/100) - i_lq1*((700*v_dc1)/81 + 2000/27) + (7*pi*v_dc1*vo_d1)/162;
 dvo_d1dt=20000*i_ld1 - 20000*io_d1 + (31367*vo_q1)/100;
 dvo_q1dt=20000*i_lq1 - 20000*io_q1 - (31367*vo_d1)/100;
 dio_d1dt=(31367*io_q1)/100 + (20000*vo_d1)/7 - io_d1*((20000000*cos(delta1)^2)/7 + (20000000*sin(delta1)^2)/7 + 600/7) + (20000000*i_lineD1*cos(delta1))/7 + (20000000*i_lineQ1*sin(delta1))/7;
 dio_q1dt=(20000*vo_q1)/7 - (31367*io_d1)/100 - io_q1*((20000000*cos(delta1)^2)/7 + (20000000*sin(delta1)^2)/7 + 600/7) + (20000000*i_lineQ1*cos(delta1))/7 - (20000000*i_lineD1*sin(delta1))/7;
 di_dc2dt=8790923519632281/8796093022208 - (9001905684103455*v_dc2)/9007199254740992 - (7201524547282765*i_dc2)/144115188075855872;
 dv_dc2dt=(900970629561481*i_dc2)/4503599627370496 - (562949953421312*P2)/(2813966534836365*v_dc2);
 dde2ta1dt=(6935975771714791*P1)/73786976294838206464 - (6935975771714791*P2)/73786976294838206464 + 200*pi;
 dP2dt=(3141*io_d2*vo_d2)/100 - (3141*P2)/100 + (3141*io_q2*vo_q2)/100;
 dQ2dt=(3141*io_q2*vo_d2)/100 - (3141*io_d2*vo_q2)/100 - (3141*Q2)/100;
 dphi_d2dt=380 - vo_d2 - (13*Q2)/10000;
 dphi_q2dt=-vo_q2;
 dgamma_d2dt=(3*io_d2)/4 - i_ld2 - (4796153459164483*Q2)/73786976294838206464 + 390*phi_d2 - vo_d2/20 - (pi*vo_q2)/200 + 19;
 dgamma_q2dt=(3*io_q2)/4 - i_lq2 + 390*phi_q2 - vo_q2/20 + (pi*vo_d2)/200;
 di_ld2dt=(13300*v_dc2)/81 - vo_d2*((35*v_dc2)/81 + 20000/27) - (91*Q2*v_dc2)/162000 + (3200000*gamma_d2*v_dc2)/243 + (175*io_d2*v_dc2)/27 + (91000*phi_d2*v_dc2)/27 - i_lq2*((pi*v_dc2)/9 - 31367/100) - i_ld2*((700*v_dc2)/81 + 2000/27) - (7*pi*v_dc2*vo_q2)/162;
 di_lq2dt=(3200000*gamma_q2*v_dc2)/243 - vo_q2*((35*v_dc2)/81 + 20000/27) + (175*io_q2*v_dc2)/27 + (91000*phi_q2*v_dc2)/27 + i_ld2*((pi*v_dc2)/9 - 31367/100) - i_lq2*((700*v_dc2)/81 + 2000/27) + (7*pi*v_dc2*vo_d2)/162;
 dvo_d2dt=20000*i_ld2 - 20000*io_d2 + (31367*vo_q2)/100;
 dvo_q2dt=20000*i_lq2 - 20000*io_q2 - (31367*vo_d2)/100;
 dio_d2dt=(31367*io_q2)/100 + (20000*vo_d2)/7 - io_d2*((20000000*cos(delta2)^2)/7 + (20000000*sin(delta2)^2)/7 + 600/7) + (20000000*i_lineD2*cos(delta2))/7 + (20000000*i_lineQ2*sin(delta2))/7;
 dio_q2dt=(20000*vo_q2)/7 - (31367*io_d2)/100 - io_q2*((20000000*cos(delta2)^2)/7 + (20000000*sin(delta2)^2)/7 + 600/7) + (20000000*i_lineQ2*cos(delta2))/7 - (20000000*i_lineD2*sin(delta2))/7;
 di_lineD1dt=(6746518852261009*i_lineD2)/2147483648 - (6748070551597029*i_lineD1)/2147483648 + (31367*i_lineQ1)/100 + (6746518852261009*io_d1*cos(delta1))/2147483648 - (6746518852261009*io_d2*cos(delta2))/2147483648 - (6746518852261009*io_q1*sin(delta1))/2147483648 + (6746518852261009*io_q2*sin(delta2))/2147483648;
 di_lineQ1dt=(6746518852261009*i_lineQ2)/2147483648 - (6748070551597029*i_lineQ1)/2147483648 - (31367*i_lineD1)/100 + (6746518852261009*io_q1*cos(delta1))/2147483648 - (6746518852261009*io_q2*cos(delta2))/2147483648 + (6746518852261009*io_d1*sin(delta1))/2147483648 - (6746518852261009*io_d2*sin(delta2))/2147483648;
 di_lineD2dt=(4652771622248973*i_lineD1)/8589934592 - (4652771622248973*i_loadD1)/8589934592 + (2325571576090593*i_lineD2)/4294967296 + (4652771622248973*i_lineQ1)/8589934592 + (31367*i_lineQ2)/100 - (4652771622248973*io_q1*cos(delta1))/8589934592 - (4652771622248973*io_d1*sin(delta1))/8589934592;
 di_lineQ2dt=(4652771622248973*i_lineQ1)/8589934592 - (4652771622248973*i_loadQ1)/8589934592 - (31367*i_lineD2)/100 + (4651957387215079*i_lineQ2)/4294967296 - (4652771622248973*io_q2*cos(delta2))/8589934592 - (4652771622248973*io_d2*sin(delta2))/8589934592;
 di_loadD1dt=1000000000000*i_lineD1 - (8396799999999999*i_loadD1)/8192 + 1000000000000*i_lineD2 + (31367*i_loadQ1)/100;
 di_loadQ1dt=1000000000000*i_lineQ1 - (8396799999999999*i_loadQ1)/8192 - (31367*i_loadD1)/100 + 1000000000000*i_lineQ2;
 

 dydt=[di_dc1dt;dv_dc1dt;ddelta1dt;dP1dt;dQ1dt;dphi_d1dt;dphi_q1dt;dgamma_d1dt;dgamma_q1dt;di_ld1dt;di_lq1dt;dvo_d1dt;dvo_q1dt;dio_d1dt;dio_q1dt;di_dc2dt;dv_dc2dt;dde2ta1dt;dP2dt;
     dQ2dt;dphi_d2dt;dphi_q2dt;dgamma_d2dt;dgamma_q2dt;di_ld2dt;di_lq2dt;dvo_d2dt;dvo_q2dt;dio_d2dt;dio_q2dt;di_lineD1dt;di_lineQ1dt;di_lineD2dt;di_lineQ2dt;di_loadD1dt;di_loadQ1dt];
end

Error: -

Out of memory.

Error in ode23tb (line 680)

yout = [yout, zeros(neq,chunk)]; %#ok<AGROW>

Error in dydt_actual (line 9)

[t, y] = ode23tb(@sysMG2, tspan, y01, options);

[Steven Lord]

Try solving this for a shorter period of time and see if the solution is wildly oscillating or increasing/decreasing rapidly. If the solution for one of the components is increasing to +Inf or decreasing to -Inf I would check the equations to make sure they're doing what I expected them to do.

Another potential approach (or avenue of investigation) would be to try loosening the tolerances you've specified and see if that lets the solver take longer and/or fewer time steps.

[Manish Kumar]

When I run it for 20 ms, the following error occurs:

Error using horzcat. Requested 36*29032000 (7.8GB) array exceeds maximum array size...

[Torsten]

Look at @Walter Roberson 's answer: You must limit the number of output times.

Answer 1

[Sam Chak]

Hi @Manish Kumar

From the simulation below, you can observe when the solutions begin to blow up. Do you really intend to log the unbounded, arbitrarily large values? If they are meaningful for your analysis, then you will need to increase the memory of your computer to store those values.

tend    = [2e-11, 2e-6 2e-4];
y01     = 0.1*ones(36,1);
% y0 =[10 2.5 0 1 0.00025 0 0 0 0 (11.4*380/10000) -(5.5*380/10000) 380.8/380 0 (11.4*380/10000) (0.4*380/10000)...
%     10 2.5 (1.9e-3) 1 1 0 0 0 0 (11.4*380/10000) -(5.5*380/10000) 380.8/380 0 (11.4*380/10000) (0.4*380/10000)...
%     3.8*380/1000 0.4*380/10000 7.6*380/10000 1.6*380/10000 22.8*380/10000 0.8*380/10000];  
options = odeset('RelTol', 1e-4, 'AbsTol', 1e-6);

for i = 1:length(tend)
    [t, y]  = ode23tb(@sysMG2, [0 tend(i)], y01, options);
    figure(i)
    plot(t, y), grid on, grid minor, xlabel('t'), xlim([0 tend(i)])
end

function dydt = sysMG2(t, y)
    i_dc1       = y(1); 
    v_dc1       = y(2);
    delta1      = y(3); 
    P1          = y(4); 
    Q1          = y(5); 
    phi_d1      = y(6); 
    phi_q1      = y(7); 
    gamma_d1    = y(8); 
    gamma_q1    = y(9);
    i_ld1       = y(10);
    i_lq1       = y(11); 
    vo_d1       = y(12); 
    vo_q1       = y(13); 
    io_d1       = y(14); 
    io_q1       = y(15);
    i_dc2       = y(16); 
    v_dc2       = y(17);
    delta2      = y(18); 
    P2          = y(19); 
    Q2          = y(20); 
    phi_d2      = y(21); 
    phi_q2      = y(22); 
    gamma_d2    = y(23); 
    gamma_q2    = y(24);
    i_ld2       = y(25); 
    i_lq2       = y(26); 
    vo_d2       = y(27); 
    vo_q2       = y(28); 
    io_d2       = y(29); 
    io_q2       = y(30); 
    i_lineD1    = y(31);
    i_lineQ1    = y(32);
    i_lineD2    = y(33);
    i_lineQ2    = y(34);
    i_loadD1    = y(35);
    i_loadQ1    = y(36);
    
    di_dc1dt    = 8790923519632281/8796093022208 - (9001905684103455*v_dc1)/9007199254740992 - (7201524547282765*i_dc1)/144115188075855872;
    dv_dc1dt    = (900970629561481*i_dc1)/4503599627370496 - (562949953421312*P1)/(2813966534836365*v_dc1);
    ddelta1dt   = 200*pi;
    dP1dt       = (3141*io_d1*vo_d1)/100 - (3141*P1)/100 + (3141*io_q1*vo_q1)/100;
    dQ1dt       = (3141*io_q1*vo_d1)/100 - (3141*io_d1*vo_q1)/100 - (3141*Q1)/100;
    dphi_d1dt   = 380 - vo_d1 - (13*Q1)/10000;
    dphi_q1dt   = -vo_q1;
    dgamma_d1dt = (3*io_d1)/4 - i_ld1 - (4796153459164483*Q1)/73786976294838206464 + 390*phi_d1 - vo_d1/20 - (pi*vo_q1)/200 + 19;
    dgamma_q1dt = (3*io_q1)/4 - i_lq1 + 390*phi_q1 - vo_q1/20 + (pi*vo_d1)/200;
    di_ld1dt    = (13300*v_dc1)/81 - vo_d1*((35*v_dc1)/81 + 20000/27) - (91*Q1*v_dc1)/162000 + (3200000*gamma_d1*v_dc1)/243 + (175*io_d1*v_dc1)/27 + (91000*phi_d1*v_dc1)/27 - i_lq1*((pi*v_dc1)/9 - 31367/100) - i_ld1*((700*v_dc1)/81 + 2000/27) - (7*pi*v_dc1*vo_q1)/162;
    di_lq1dt    = (3200000*gamma_q1*v_dc1)/243 - vo_q1*((35*v_dc1)/81 + 20000/27) + (175*io_q1*v_dc1)/27 + (91000*phi_q1*v_dc1)/27 + i_ld1*((pi*v_dc1)/9 - 31367/100) - i_lq1*((700*v_dc1)/81 + 2000/27) + (7*pi*v_dc1*vo_d1)/162;
    dvo_d1dt    = 20000*i_ld1 - 20000*io_d1 + (31367*vo_q1)/100;
    dvo_q1dt    = 20000*i_lq1 - 20000*io_q1 - (31367*vo_d1)/100;
    dio_d1dt    = (31367*io_q1)/100 + (20000*vo_d1)/7 - io_d1*((20000000*cos(delta1)^2)/7 + (20000000*sin(delta1)^2)/7 + 600/7) + (20000000*i_lineD1*cos(delta1))/7 + (20000000*i_lineQ1*sin(delta1))/7;
    dio_q1dt    = (20000*vo_q1)/7 - (31367*io_d1)/100 - io_q1*((20000000*cos(delta1)^2)/7 + (20000000*sin(delta1)^2)/7 + 600/7) + (20000000*i_lineQ1*cos(delta1))/7 - (20000000*i_lineD1*sin(delta1))/7;
    di_dc2dt    = 8790923519632281/8796093022208 - (9001905684103455*v_dc2)/9007199254740992 - (7201524547282765*i_dc2)/144115188075855872;
    dv_dc2dt    = (900970629561481*i_dc2)/4503599627370496 - (562949953421312*P2)/(2813966534836365*v_dc2);
    dde2ta1dt   = (6935975771714791*P1)/73786976294838206464 - (6935975771714791*P2)/73786976294838206464 + 200*pi;
    dP2dt       = (3141*io_d2*vo_d2)/100 - (3141*P2)/100 + (3141*io_q2*vo_q2)/100;
    dQ2dt       = (3141*io_q2*vo_d2)/100 - (3141*io_d2*vo_q2)/100 - (3141*Q2)/100;
    dphi_d2dt   = 380 - vo_d2 - (13*Q2)/10000;
    dphi_q2dt   = -vo_q2;
    dgamma_d2dt = (3*io_d2)/4 - i_ld2 - (4796153459164483*Q2)/73786976294838206464 + 390*phi_d2 - vo_d2/20 - (pi*vo_q2)/200 + 19;
    dgamma_q2dt = (3*io_q2)/4 - i_lq2 + 390*phi_q2 - vo_q2/20 + (pi*vo_d2)/200;
    di_ld2dt    = (13300*v_dc2)/81 - vo_d2*((35*v_dc2)/81 + 20000/27) - (91*Q2*v_dc2)/162000 + (3200000*gamma_d2*v_dc2)/243 + (175*io_d2*v_dc2)/27 + (91000*phi_d2*v_dc2)/27 - i_lq2*((pi*v_dc2)/9 - 31367/100) - i_ld2*((700*v_dc2)/81 + 2000/27) - (7*pi*v_dc2*vo_q2)/162;
    di_lq2dt    = (3200000*gamma_q2*v_dc2)/243 - vo_q2*((35*v_dc2)/81 + 20000/27) + (175*io_q2*v_dc2)/27 + (91000*phi_q2*v_dc2)/27 + i_ld2*((pi*v_dc2)/9 - 31367/100) - i_lq2*((700*v_dc2)/81 + 2000/27) + (7*pi*v_dc2*vo_d2)/162;
    dvo_d2dt    = 20000*i_ld2 - 20000*io_d2 + (31367*vo_q2)/100;
    dvo_q2dt    = 20000*i_lq2 - 20000*io_q2 - (31367*vo_d2)/100;
    dio_d2dt    = (31367*io_q2)/100 + (20000*vo_d2)/7 - io_d2*((20000000*cos(delta2)^2)/7 + (20000000*sin(delta2)^2)/7 + 600/7) + (20000000*i_lineD2*cos(delta2))/7 + (20000000*i_lineQ2*sin(delta2))/7;
    dio_q2dt    = (20000*vo_q2)/7 - (31367*io_d2)/100 - io_q2*((20000000*cos(delta2)^2)/7 + (20000000*sin(delta2)^2)/7 + 600/7) + (20000000*i_lineQ2*cos(delta2))/7 - (20000000*i_lineD2*sin(delta2))/7;
    di_lineD1dt = (6746518852261009*i_lineD2)/2147483648 - (6748070551597029*i_lineD1)/2147483648 + (31367*i_lineQ1)/100 + (6746518852261009*io_d1*cos(delta1))/2147483648 - (6746518852261009*io_d2*cos(delta2))/2147483648 - (6746518852261009*io_q1*sin(delta1))/2147483648 + (6746518852261009*io_q2*sin(delta2))/2147483648;
    di_lineQ1dt = (6746518852261009*i_lineQ2)/2147483648 - (6748070551597029*i_lineQ1)/2147483648 - (31367*i_lineD1)/100 + (6746518852261009*io_q1*cos(delta1))/2147483648 - (6746518852261009*io_q2*cos(delta2))/2147483648 + (6746518852261009*io_d1*sin(delta1))/2147483648 - (6746518852261009*io_d2*sin(delta2))/2147483648;
    di_lineD2dt = (4652771622248973*i_lineD1)/8589934592 - (4652771622248973*i_loadD1)/8589934592 + (2325571576090593*i_lineD2)/4294967296 + (4652771622248973*i_lineQ1)/8589934592 + (31367*i_lineQ2)/100 - (4652771622248973*io_q1*cos(delta1))/8589934592 - (4652771622248973*io_d1*sin(delta1))/8589934592;
    di_lineQ2dt = (4652771622248973*i_lineQ1)/8589934592 - (4652771622248973*i_loadQ1)/8589934592 - (31367*i_lineD2)/100 + (4651957387215079*i_lineQ2)/4294967296 - (4652771622248973*io_q2*cos(delta2))/8589934592 - (4652771622248973*io_d2*sin(delta2))/8589934592;
    di_loadD1dt = 1000000000000*i_lineD1 - (8396799999999999*i_loadD1)/8192 + 1000000000000*i_lineD2 + (31367*i_loadQ1)/100;
    di_loadQ1dt = 1000000000000*i_lineQ1 - (8396799999999999*i_loadQ1)/8192 - (31367*i_loadD1)/100 + 1000000000000*i_lineQ2;
        
    dydt        = [di_dc1dt;
                   dv_dc1dt;
                   ddelta1dt;
                   dP1dt;
                   dQ1dt;
                   dphi_d1dt;
                   dphi_q1dt;
                   dgamma_d1dt;
                   dgamma_q1dt;
                   di_ld1dt;
                   di_lq1dt;
                   dvo_d1dt;
                   dvo_q1dt;
                   dio_d1dt;
                   dio_q1dt;
                   di_dc2dt;
                   dv_dc2dt;
                   dde2ta1dt;
                   dP2dt;
                   dQ2dt;
                   dphi_d2dt;
                   dphi_q2dt;
                   dgamma_d2dt;
                   dgamma_q2dt;
                   di_ld2dt;
                   di_lq2dt;
                   dvo_d2dt;
                   dvo_q2dt;
                   dio_d2dt;
                   dio_q2dt;
                   di_lineD1dt;
                   di_lineQ1dt;
                   di_lineD2dt;
                   di_lineQ2dt;
                   di_loadD1dt;
                   di_loadQ1dt];
end

[Manish Kumar]

Thank you!

Answer 2

[Walter Roberson]

If you use something like

tspan = linspace(0, 2, 1001);

then it should not run out of memory.

It is running out of memory trying to store the dy results of an oscillating function.

[Manish Kumar]

I’ve implemented your suggestions, and the code has been running for the past 24 hours....

[Torsten]

We might be able to help if you have technical problems/syntax errors with MATLAB, but you are the one who is responsible for the equations to be solved. And the long runtime is a problem inherent to your equations ...

[Walter Roberson]

I would experiment with something like tspan = [0 0.01] to get an idea of how the system reacts.