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zhaoshans

Ìú¸Ëľ³æ (СÓÐÃûÆø)

[½»Á÷] ¡¾ÇóÖú¡¿ode45ÎÊÌ⡾ÒÑÍê³É¡¿

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%µÚÒ»¸öMÎļþ
function dy=ivpode1(t,y)
dy=zeros(2,1);
dy(1)=y(2);
dy(2)=(1-y(1)^2)*y(2)-y(1);

%µÚ¶þ¸öMÎļþ
function df=ivpode2(t,f)
global y
u=ones(length(t),1)*10;
for i=1:1:20
u(i<=t&t<(i+1))=y(i,1);
end
df=zeros(2,1);
df(1)=f(2);
df(2)=u*(1-f(1)^2)*f(2)-f(1);

t=0:1:20;
>> [t,y]=ode45(@ivpode1,t,[2,0]);
>> [t,f]=ode45(@ivpode2,t,[2,0]);
??? Attempted to access y(7,1); index out of bounds because size(y)=[6,1].

Error in ==> ivpode2 at 5
u(i<=t&t<(i+1))=y(i,1);

Error in ==> funfun\private\odearguments at 110
f0 = feval(ode,t0,y0,args{:});   % ODE15I sets args{1} to yp0.

Error in ==> ode45 at 173
[neq, tspan, ntspan, next, t0, tfinal, tdir, y0, f0, odeArgs, ...


[ Last edited by nono2009 on 2009-9-25 at 07:02 ]
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zhaoshans

Ìú¸Ëľ³æ (СÓÐÃûÆø)

5Â¥2009-05-21 14:46:09
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sitonyl

Ìú¸Ëľ³æ (ÎÄ̳¾«Ó¢)

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global y
t=0:1:20;
[t,y]=ode45(@ivpode1,t,[2,0]);
[t,f]=ode45(@ivpode2,t,[2,0]);
zz
2Â¥2009-05-20 22:14:32
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zhaoshans

Ìú¸Ëľ³æ (СÓÐÃûÆø)

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global y
t=0:1:20;
[t,y]=ode45(@ivpode1,t,[2,0]);
[t,f]=ode45(@ivpode2,t,[2,0]);


Warning: Failure at t=5.188906e+000.  Unable to meet integration tolerances without reducing the step size below the smallest value allowed (1.421085e-014) at time t.
> In ode45 at 355
3Â¥2009-05-21 11:44:16
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sitonyl

Ìú¸Ëľ³æ (ÎÄ̳¾«Ó¢)

¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï
zhaoshans(½ð±Ò+5,VIP+0):ºÜÄÍÐĵİïæ 5-21 14:46
woshilsh(½ð±Ò+3,VIP+0):ÎÊÌâµÃµ½Â¥Ö÷ÈϿɣ¬¼Î½±3½ð±Ò£¡ 5-21 15:19
woshilsh(½ð±Ò+0,VIP+0):ÐÖµÜÒÔºó³£À´¹þ£¡ 5-21 15:19
ÒýÓûØÌû:
Originally posted by zhaoshans at 2009-5-21 11:44:
лл¹Ø×¢£¬µ«ÊÇÎÒ°´ÕÕÏÂÃæÖ¸ÁîÊäÈëºó£¬»¹ÊÇÔËÐÐÓÐÎÊÌâ
global y
t=0:1:20;
[t,y]=ode45(@ivpode1,t,[2,0]);
[t,f]=ode45(@ivpode2,t,[2,0]);


Warning: Failure at t=5.188906e+000.  Unable to meet int ...

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t=0:0.01:20;
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4Â¥2009-05-21 12:05:14
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