ode 45, big matrices, I can not get result because of

3 visualizzazioni (ultimi 30 giorni)
Gloria
Gloria il 7 Set 2020
Commentato: Rik il 23 Set 2020
function deneme
S=0.02;
rpm=111; %rpm
w(1)=rpm*2*pi/60;
AA=0.4;
P=0.8;
Z=4;
DD=6.15;
p=1025;
n=1.85;
AR=0.22087*Z/AA;
c211=0.13925-0.48179*AA-0.14175*P+0.27711*AA^2-0.0094311*P^2+0.17407*AA*P;
LSC=0.80988-0.63077*AR^-2+1.3909*P*AR^-1+7.5424*AR^-3-15.689*P*AR^-3-8.0097*AR^-4+17.665*P*AR^-4;
c21=p*n*DD^4*c211*LSC;
m211=0.0012195+0.017664*AA-0.0085938*P-0.023615*AA^2+0.0094301*P^2-0.026146*AA*P;
LSCC=0.65348+0.28788*P+0.39805*AR^-1-0.42582*AR^-2-0.61189*P*AR^-1+0.33373*P*AR^-2;
m21=p*DD^4*m211*LSCC;
J(1)=5000; J(2)=2479; J(3)=7040; J(4)=7519; J(5)=7040; J(6)=7040; J(7)=7519; J(8)=4257; J(9)=4893; J(10)=124; J(11)=47; J(12)=58; J(13)=93; J(14)=35026;
kt(1)=0.17112e10 ;kt(2)=1/6.63e-10; kt(3)=1/8.30e-10; kt(4)=1/8.30e-10; kt(5)=1/8.38e-10; kt(6)=1/8.30e-10; kt(7)=1/6.48e-10; kt(8)=1/4.86e-10; kt(9)=1/2.607e-8; kt(10)=1/1.743e-9; kt(11)=1/9.148e-10; kt(12)=1/2.603e-9; kt(13)=1/3.141e-9;
dt(1)=0.2590e10; dx(1)=0.2590e10;
m(1)=8322; m(2)=13914; m(3)=10941; m(4)=1620; m(5)=5897; m(6)=6138; m(7)=23067;
kx(1)=0.77e11 ;kx(2)=0.47e10; kx(3)=0.64e11; kx(4)=0.55e11; kx(5)=1/8.38e-10; kx(6)=1/8.30e-10;
%Forcing function
ft=@(time) 1000*sin(w(1)*time); %N.m %516
fx=@(time) 1000*sin(w(1)*time); %N %3424.9 %
%Mass Matrix
JJ = [J(1) 0 0 0 0 0 0 0 0 0 0 0 0 0
0 J(2) 0 0 0 0 0 0 0 0 0 0 0 0
0 0 J(3) 0 0 0 0 0 0 0 0 0 0 0
0 0 0 J(4) 0 0 0 0 0 0 0 0 0 0
0 0 0 0 J(5) 0 0 0 0 0 0 0 0 0
0 0 0 0 0 J(6) 0 0 0 0 0 0 0 0
0 0 0 0 0 0 J(7) 0 0 0 0 0 0 0
0 0 0 0 0 0 0 J(8) 0 0 0 0 0 0
0 0 0 0 0 0 0 0 J(9) 0 0 0 0 0
0 0 0 0 0 0 0 0 0 J(10) 0 0 0 0
0 0 0 0 0 0 0 0 0 0 J(11) 0 0 0
0 0 0 0 0 0 0 0 0 0 0 J(12) 0 0
0 0 0 0 0 0 0 0 0 0 0 0 J(13) 0
0 0 0 0 0 0 0 0 0 0 0 0 0 J(14)];
M= [m(1) 0 0 0 0 0 0
0 m(2) 0 0 0 0 0
0 0 m(3) 0 0 0 0
0 0 0 m(4) 0 0 0
0 0 0 0 m(5) 0 0
0 0 0 0 0 m(6) 0
0 0 0 0 0 0 m(7)];
W=[0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0];
Y= [0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 ];
AA=[JJ W
Y M];
%Damping Matrix
DT=[dt(1) -dt(1) 0 0 0 0 0 0 0 0 0 0 0 0
-dt(1) dt(1) 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 ];
DX=[0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0];
D=[DT W
Y DX];
%Stiffness Matrix
KT = [kt(1) -kt(1) 0 0 0 0 0 0 0 0 0 0 0 0
-kt(1) kt(1)+kt(2) -kt(2) 0 0 0 0 0 0 0 0 0 0 0
0 -kt(2) kt(2)+kt(3) -kt(3) 0 0 0 0 0 0 0 0 0 0
0 0 -kt(3) kt(3)+kt(4) -kt(4) 0 0 0 0 0 0 0 0 0
0 0 0 kt(4) kt(4)+kt(5) -kt(5) 0 0 0 0 0 0 0 0
0 0 0 0 -kt(5) kt(5)+kt(6) -kt(6) 0 0 0 0 0 0 0
0 0 0 0 0 -kt(6) kt(6)+kt(7) -kt(7) 0 0 0 0 0 0
0 0 0 0 0 0 -kt(7) kt(7)+kt(8) -kt(8) 0 0 0 0 0
0 0 0 0 0 0 0 -kt(8) kt(8)+kt(9) -kt(9) 0 0 0 0
0 0 0 0 0 0 0 0 -kt(9) kt(9)+kt(10) -kt(10) 0 0 0
0 0 0 0 0 0 0 0 0 -kt(10) kt(10)+kt(11) -kt(11) 0 0
0 0 0 0 0 0 0 0 0 0 -kt(11) kt(11)+kt(12) -kt(12) 0
0 0 0 0 0 0 0 0 0 0 0 -kt(12) kt(12)+kt(13) -kt(13)
0 0 0 0 0 0 0 0 0 0 0 0 -kt(13) kt(13)];
KX = [kx(1) -kx(1) 0 0 0 0 0
-kx(1) kx(1)+kx(2) -kx(2) 0 0 0 0
0 -kx(2) kx(2)+kx(3) -kx(3) 0 0 0
0 0 -kx(3) kx(3)+kx(4) -kx(4) 0 0
0 0 0 -kx(4) kx(4)+kx(5) -kx(5) 0
0 0 0 0 kx(5) kx(5)+kx(6) -kx(6)
0 0 0 0 0 -kx(6) kx(6)] ; % K matrix
K=[KT W
Y KX];
KT=S*[ W KT
KX Y];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
ZERO=zeros(21,21);
I=eye(21,21);
A=[ZERO , I; -inv(AA)*(K-KT), -inv(AA)*D];
B=[ZERO; inv(AA)];
F=@(TIME) [0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ;0 ; 0 ; 0 ; ft(TIME) ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; fx(TIME)]; % Force Vector
sdot=@(t,s) A*s(1:42)+B*F(t);
%%%%%%%% Initial Conditions %%%%%%%%%%%%
IC=[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Time span(seconds)
t0=0; tf=30;
tspan=[t0,tf];
%Numerical Integration
[time,state_values]=ode45(sdot,tspan,IC);
theta14=state_values(:,14);
%Plot Results
figure(1), clf
plot(time,theta14),xlabel('time (s)'), ylabel('angular displacement (rad)')
title('\theta Angular Displacement vs. Time')
end
Error using .'
Out of memory. Type HELP MEMORY for your options.
Error in odefinalize (line 47)
solver_output{2} = yout(:,1:nout).';
Error in ode45 (line 474)
solver_output = odefinalize(solver_name, sol,...
Error in deneme (line 169)
[time,state_values]=ode45(sdot,tspan,IC);
  2 Commenti
Walter Roberson
Walter Roberson il 7 Set 2020
The code finishes for me. It peaked at about 18 Gigabytes.
The angular displacement peaks about 1E+297 which suggests strongly that something is wrong with the equations.
Rik
Rik il 23 Set 2020
Before you try to delete it I will post a copy of your code. If you didn't want it online you shouldn't have posted it. You can still use it your thesis, since it is your own code. You can't however claim it hasn't been published before.
Original title:
ode 45, big matrices, I can not get result because of
function deneme
S=0.02;
rpm=111; %rpm
w(1)=rpm*2*pi/60;
AA=0.4;
P=0.8;
Z=4;
DD=6.15;
p=1025;
n=1.85;
AR=0.22087*Z/AA;
c211=0.13925-0.48179*AA-0.14175*P+0.27711*AA^2-0.0094311*P^2+0.17407*AA*P;
LSC=0.80988-0.63077*AR^-2+1.3909*P*AR^-1+7.5424*AR^-3-15.689*P*AR^-3-8.0097*AR^-4+17.665*P*AR^-4;
c21=p*n*DD^4*c211*LSC;
m211=0.0012195+0.017664*AA-0.0085938*P-0.023615*AA^2+0.0094301*P^2-0.026146*AA*P;
LSCC=0.65348+0.28788*P+0.39805*AR^-1-0.42582*AR^-2-0.61189*P*AR^-1+0.33373*P*AR^-2;
m21=p*DD^4*m211*LSCC;
J(1)=5000; J(2)=2479; J(3)=7040; J(4)=7519; J(5)=7040; J(6)=7040; J(7)=7519; J(8)=4257; J(9)=4893; J(10)=124; J(11)=47; J(12)=58; J(13)=93; J(14)=35026;
kt(1)=0.17112e10 ;kt(2)=1/6.63e-10; kt(3)=1/8.30e-10; kt(4)=1/8.30e-10; kt(5)=1/8.38e-10; kt(6)=1/8.30e-10; kt(7)=1/6.48e-10; kt(8)=1/4.86e-10; kt(9)=1/2.607e-8; kt(10)=1/1.743e-9; kt(11)=1/9.148e-10; kt(12)=1/2.603e-9; kt(13)=1/3.141e-9;
dt(1)=0.2590e10; dx(1)=0.2590e10;
m(1)=8322; m(2)=13914; m(3)=10941; m(4)=1620; m(5)=5897; m(6)=6138; m(7)=23067;
kx(1)=0.77e11 ;kx(2)=0.47e10; kx(3)=0.64e11; kx(4)=0.55e11; kx(5)=1/8.38e-10; kx(6)=1/8.30e-10;
%Forcing function
ft=@(time) 1000*sin(w(1)*time); %N.m %516
fx=@(time) 1000*sin(w(1)*time); %N %3424.9 %
%Mass Matrix
JJ = [J(1) 0 0 0 0 0 0 0 0 0 0 0 0 0
0 J(2) 0 0 0 0 0 0 0 0 0 0 0 0
0 0 J(3) 0 0 0 0 0 0 0 0 0 0 0
0 0 0 J(4) 0 0 0 0 0 0 0 0 0 0
0 0 0 0 J(5) 0 0 0 0 0 0 0 0 0
0 0 0 0 0 J(6) 0 0 0 0 0 0 0 0
0 0 0 0 0 0 J(7) 0 0 0 0 0 0 0
0 0 0 0 0 0 0 J(8) 0 0 0 0 0 0
0 0 0 0 0 0 0 0 J(9) 0 0 0 0 0
0 0 0 0 0 0 0 0 0 J(10) 0 0 0 0
0 0 0 0 0 0 0 0 0 0 J(11) 0 0 0
0 0 0 0 0 0 0 0 0 0 0 J(12) 0 0
0 0 0 0 0 0 0 0 0 0 0 0 J(13) 0
0 0 0 0 0 0 0 0 0 0 0 0 0 J(14)];
M= [m(1) 0 0 0 0 0 0
0 m(2) 0 0 0 0 0
0 0 m(3) 0 0 0 0
0 0 0 m(4) 0 0 0
0 0 0 0 m(5) 0 0
0 0 0 0 0 m(6) 0
0 0 0 0 0 0 m(7)];
W=[0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0];
Y= [0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 ];
AA=[JJ W
Y M];
%Damping Matrix
DT=[dt(1) -dt(1) 0 0 0 0 0 0 0 0 0 0 0 0
-dt(1) dt(1) 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 ];
DX=[0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0
0 0 0 0 0 0 0];
D=[DT W
Y DX];
%Stiffness Matrix
KT = [kt(1) -kt(1) 0 0 0 0 0 0 0 0 0 0 0 0
-kt(1) kt(1)+kt(2) -kt(2) 0 0 0 0 0 0 0 0 0 0 0
0 -kt(2) kt(2)+kt(3) -kt(3) 0 0 0 0 0 0 0 0 0 0
0 0 -kt(3) kt(3)+kt(4) -kt(4) 0 0 0 0 0 0 0 0 0
0 0 0 kt(4) kt(4)+kt(5) -kt(5) 0 0 0 0 0 0 0 0
0 0 0 0 -kt(5) kt(5)+kt(6) -kt(6) 0 0 0 0 0 0 0
0 0 0 0 0 -kt(6) kt(6)+kt(7) -kt(7) 0 0 0 0 0 0
0 0 0 0 0 0 -kt(7) kt(7)+kt(8) -kt(8) 0 0 0 0 0
0 0 0 0 0 0 0 -kt(8) kt(8)+kt(9) -kt(9) 0 0 0 0
0 0 0 0 0 0 0 0 -kt(9) kt(9)+kt(10) -kt(10) 0 0 0
0 0 0 0 0 0 0 0 0 -kt(10) kt(10)+kt(11) -kt(11) 0 0
0 0 0 0 0 0 0 0 0 0 -kt(11) kt(11)+kt(12) -kt(12) 0
0 0 0 0 0 0 0 0 0 0 0 -kt(12) kt(12)+kt(13) -kt(13)
0 0 0 0 0 0 0 0 0 0 0 0 -kt(13) kt(13)];
KX = [kx(1) -kx(1) 0 0 0 0 0
-kx(1) kx(1)+kx(2) -kx(2) 0 0 0 0
0 -kx(2) kx(2)+kx(3) -kx(3) 0 0 0
0 0 -kx(3) kx(3)+kx(4) -kx(4) 0 0
0 0 0 -kx(4) kx(4)+kx(5) -kx(5) 0
0 0 0 0 kx(5) kx(5)+kx(6) -kx(6)
0 0 0 0 0 -kx(6) kx(6)] ; % K matrix
K=[KT W
Y KX];
KT=S*[ W KT
KX Y];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
ZERO=zeros(21,21);
I=eye(21,21);
A=[ZERO , I; -inv(AA)*(K-KT), -inv(AA)*D];
B=[ZERO; inv(AA)];
F=@(TIME) [0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ;0 ; 0 ; 0 ; ft(TIME) ; 0 ; 0 ; 0 ; 0 ; 0 ; 0 ; fx(TIME)]; % Force Vector
sdot=@(t,s) A*s(1:42)+B*F(t);
%%%%%%%% Initial Conditions %%%%%%%%%%%%
IC=[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Time span(seconds)
t0=0; tf=30;
tspan=[t0,tf];
%Numerical Integration
[time,state_values]=ode45(sdot,tspan,IC);
theta14=state_values(:,14);
%Plot Results
figure(1), clf
plot(time,theta14),xlabel('time (s)'), ylabel('angular displacement (rad)')
title('\theta Angular Displacement vs. Time')
end
Error using .'
Out of memory. Type HELP MEMORY for your options.
Error in odefinalize (line 47)
solver_output{2} = yout(:,1:nout).';
Error in ode45 (line 474)
solver_output = odefinalize(solver_name, sol,...
Error in deneme (line 169)
[time,state_values]=ode45(sdot,tspan,IC);

Accedi per commentare.

Risposte (1)

Walter Roberson
Walter Roberson il 7 Set 2020
By the way, you can reduce the equations to
[ S(22);
S(23);
S(24);
S(25);
S(26);
S(27);
S(28);
S(29);
S(30);
S(31);
S(32);
S(33);
S(34);
S(35);
S(36);
S(37);
S(38);
S(39);
S(40);
S(41);
S(42);
342240.0*S(2) - 342240.0*S(1) + 6844.8*S(8) - 6844.8*S(9) - 518000.0*S(22) + 518000.0*S(23);
690278.33803953207097947597503662*S(1) - 1298707.3924738543573766946792603*S(2) + 608429.05443432228639721870422363*S(3) - 13805.566760790641637868247926235*S(8) + 25974.147849477089039282873272896*S(9) - 12168.581088686445582425221800804*S(10) + 1044776.1194029850885272026062012*S(22) - 1044776.1194029850885272026062012*S(23);
214246.53777594954590313136577606*S(2) - 385385.63963794300798326730728149*S(3) + 171139.10186199340387247502803802*S(4) - 4284.9307555189907361636869609356*S(9) + 7707.71279275885990500682964921*S(10) - 3422.7820372398682593484409153461*S(11);
160236.63746621011523529887199402*S(3) - 320473.27493242023047059774398804*S(4) + 160236.63746621011523529887199402*S(5) - 3204.7327493242019045283086597919*S(10) + 6409.4654986484038090566173195839*S(11) - 3204.7327493242019045283086597919*S(12);
169505.31568669993430376052856445*S(6) - 340644.41754869336728006601333618*S(5) - 171139.10186199340387247502803802*S(4) + 3422.7820372398682593484409153461*S(11) + 6812.8883509738670909428037703037*S(12) - 3390.1063137339988315943628549576*S(13);
169505.31568669993430376052856445*S(5) - 340644.41754869336728006601333618*S(6) + 171139.10186199340387247502803802*S(7) - 3390.1063137339988315943628549576*S(12) + 6812.8883509738670909428037703037*S(13) - 3422.7820372398682593484409153461*S(14);
160236.63746621011523529887199402*S(6) - 365478.00952941132709383964538574*S(7) + 205241.37206320121185854077339172*S(8) - 3204.7327493242019045283086597919*S(13) + 7309.5601905882276696502231061459*S(14) - 4104.8274412640248556272126734257*S(15);
362511.1290916631114669144153595*S(7) - 845859.30121388053521513938903809*S(8) + 483348.1721222175401635468006134*S(9) - 7250.2225818332626658957451581955*S(14) + 16917.186024277612887090072035789*S(15) - 9666.963442444350221194326877594*S(16);
420521.80027064785826951265335083*S(8) - 428361.2170305839972570538520813*S(9) + 7839.4167599361271641100756824017*S(10) - 8410.4360054129574564285576343536*S(15) + 8567.2243406116795085836201906204*S(16) - 156.78833519872256374583230353892*S(17);
309340.85650296346284449100494385*S(9) - 4936142.995936272665858268737793*S(10) + 4626802.1394333085045218467712402*S(11) - 6186.8171300592694024089723825455*S(16) + 98722.859918725444003939628601074*S(17) - 92536.042788666178239509463310242*S(18);
12206882.240207027643918991088867*S(10) - 35465076.101904504001140594482422*S(11) + 23258193.861697476357221603393555*S(12) - 244137.64480414055287837982177734*S(17) + 709301.5220380900427699089050293*S(18) - 465163.87723394948989152908325195*S(19);
18847157.094823814928531646728516*S(11) - 25470814.148356214165687561035156*S(12) + 6623657.0535323964431881904602051*S(13) - 376943.14189647632883861660957336*S(18) + 509416.28296712430892512202262878*S(19) - 132473.14107064792187884449958801*S(20);
4130882.8936008499003946781158447*S(12) - 7554215.644967615604400634765625*S(13) + 3423332.7513667661696672439575195*S(14) - 82617.657872016992769204080104828*S(19) + 151084.31289935231325216591358185*S(20) - 68466.65502733532048296183347702*S(21);
9089.5319441874398762593045830727*S(13) - 9089.5319441874398762593045830727*S(14) - 181.79063888374878388276556506753*S(20) + 181.79063888374878388276556506753*S(21) + 0.028550219836692742534117512704848*sin(11.623892818282234982311780518134*T);
185051.67027156930998899042606354*S(1) - 185051.67027156930998899042606354*S(2) - 9252583.5135784670710563659667969*S(15) + 9252583.5135784670710563659667969*S(16);
117435.67629725455481093376874924*S(2) - 110679.89075751040945760905742645*S(1) - 6755.7855397441417153459042310715*S(3) + 5533994.5378755209967494010925293*S(15) - 5871783.814862728118896484375*S(16) + 337789.2769872071221470832824707*S(17);
125582.67068823690351564437150955*S(3) - 8591.5364226304718613391742110252*S(2) - 116991.1342656064371112734079361*S(4) + 429576.82113152364036068320274353*S(16) - 6279133.5344118447974324226379395*S(17) + 5849556.713280322030186653137207*S(18);
1469135.8024691357277333736419678*S(4) - 790123.45679012348409742116928101*S(3) - 679012.34567901236005127429962158*S(5) + 39506172.839506171643733978271484*S(17) - 73456790.123456791043281555175781*S(18) + 33950617.283950619399547576904297*S(19);
190582.72824295191094279289245605*S(5) - 186535.5265389181149657815694809*S(4) - 4047.2017040338059814530424773693*S(6) + 9326776.3269459046423435211181641*S(18) - 9529136.4121475946158170700073242*S(19) + 202360.0852016902936156839132309*S(20);
3888.2939799099626725364942103624*S(5) + 7814.0654921564073447370901703835*S(6) - 3925.7715122464437627058941870928*S(7) - 194414.69899549815454520285129547*S(19) - 390703.27460782037815079092979431*S(20) + 196288.57561232222360558807849884*S(21);
1044.6258959625731677078874781728*S(7) - 1044.6258959625731677078874781728*S(6) + 52231.294798128656111657619476318*S(20) - 52231.294798128656111657619476318*S(21) + 0.043351974682446785451077296570859*sin(11.623892818282234982311780518134*T);
]
  2 Commenti
Walter Roberson
Walter Roberson il 7 Set 2020
I just noticed that it ends after about 10 seconds instead of continuing to 30. That implies it decided that the equations were singular.
Walter Roberson
Walter Roberson il 7 Set 2020
Your 22'nd and 23'rd output get very bumpy starting at about pi/2 seconds. Because of that, ode45 ends up needing to integrate a lot of points.
A situation like this often hints that you should be using a stiff solver.

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