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im solving 4 ODe with boundary conditions.. i got this error Error, (in dsolve/numeric/bvp/convertsys) too few boundary conditions: expected 8, got 7


i want to find initial condition for F(0),G(0), H(0) and thetap(0) which is are missing in this problem.. then i facing this error Error, (in dsolve/numeric/bvp) Newton iteration is not converging



Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/hydronew2.mw .

Download hydronew2.mw

i am solving 4 ODE with boundary condition..

> restart;
> with*plots;

 

then i got this error..

Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system

 

i dont know where i need to change.. could you help me..

 

 

 

Dear all;

Please I need your help to find the error in my code.

I want to solve an ode, with condition on step size.

ode := diff(y(x), x) = 2*x+y(x);
f:=(x,y)->2*x-y;

analyticsol := rhs(dsolve({ode, y(0) = 1}));
RKadaptivestepsize := proc (f, a, b, epsilon, N)
local x, y, n, h,k,z,R,p;
p:=2;
h := evalf(b-a)/N; ## we begin with this setpsize
x[0] := a; y[0] := 1; ## Initialisation
for n from 0 to N-1 do  ##loop
x[n+1] := a+(n+1)*h;  ## noeuds
k[1] := f(x[n], y[n]);
k[2] := f(x[n]+h, y[n]+h*k[1]);
k[3] := f(x[n]+h/2, y[n]+h/4*(k[1]+k[2]));
z[n+1] := z[n]+(h/2)*(k[1]+k[2]);## 2-stage runge Kutta.
y[n+1] := y[n]+(h/6)*(k[1]+k[2]+4*k[3]);
R:=abs(y[n+1]-z[n+1]); ## local erreur
hstar:=sqrt(epsilon/R)
if R=<=epsilon    then
   x[n] := x[n+1]+h;
   y[n]:=y[n+1];
   n:=n+1;

else

h:=hstar;
end if
 end do;
[seq([x[n], y[n]], n = 0 .. N)];
[seq([x[n], z[n]], n = 0 .. N)];
end proc:

epsilon:=1e-8;
RKadaptivestepsize((x,y)->2*x-y,0,1, epsilon,20)

Is there any simple way to print the sum of a series with exceptions?

For example, the following works (sort of), but its not consistent with mathematical notation, where one would expect to see something like a Sigma^' printed out, and the condition, alongw ith ther limits appear under the Sigma sign:

[Sum(1/(k^2-p),k=0..infinity),And(k<>p)]

Hello everyone,

I need help to type in the following type of initial condition.

diff(1/x*diff(F(x),x),x)=0 at x =0.

Thanks

Hello,

I would like to solve the differential equation in the following link:

http://www.utdallas.edu/~frensley/technical/nanomes91/node2.html

 

Without using any explicit discretization. Is it possible to solve this equation with a Maple dsolve comand and some boundary condition option?

In a trivial example of where x goes from 0 to 1 of d n(x)/dx =a, where n(0)=1, n(1)=2, so that the integral is solved easily, how can i do this in maple however I can only solve an eqation with the initial condition, if i try anything else then i get errors such as, 

fx := diff(n(x), x)-a

A := rhs(dsolve({fx, x = 0 .. 1, n(0) = 1, n(1) = 2}, n(x)));

Error, (in dsolve) invalid terms in sum: 0 .. 1

 

 

 

I am trying to solve a nonlinear second order ODE with a parameter to be determined. I can set up most of the problem but I am having trouble trying to tell the computer the following boundary condition,

 

diff(f(x),x) = -K on f(x)=0.

 

(K will be inputted and is not to be solved for) As i said before, the other boundary conditions are fine and the numerical solution works if i use different boundary conditions. 

 

For other boundary conditions (for example df/dx = 0 at x=0) I write in the form 

D(f)(0)=0

 

I hope this makes sense and someone has a solution. Thanks in advance.

 

Matt

PDE.mw

Hi i attach the file that i have problem with.I guess it is not the first problem with datatype=float[8], but i will appreciate if someone could help me with it.

After calling pdsolve i get the answer in the module "structure", i try to plot it and i get :

Error, (in pdsolve/numeric/plot) unable to compute solution for t<HFloat(0.0):
unable to store [.02091392039809]-5.00000000000000 when datatype=float[8]

 

I am not sure how to interpret it and what should i change to make it work.

My PDE is a Bellman equation and my problem is that i actually know only one boundary condition "icond", is there a way to solve it without other conditions?

Thank you

Sorry if this is a bit vague...

I have a list.  I am applying a loop with a condition.  When the condition is met it stops (of course) but how do I get the condition to continue testing against the rest of the list without incrementing the next loop value?

am trying to solve this code by changing boundary conditions but all the time it gives error that some points are not included i dont know what the reason is or may be my boundary conditions are not utilized please check it am attaching my file trytimg.mw

Hi, i´m trying to understand how does maplesim simulate a model with differential equatyions and on maplesim help i found this:

 

"Numeric Integration and Event Handling


During numeric solving (or "integration"), inequality conditions that are part of the model
are monitored and an event is triggered when one or more of these conditions change.
Whenever such an event is encountered, the numeric solver is stopped and the simulation

Hello,

I'm trying to solve the effects (deflictions, tensions, etc) of a load on a timoshenko beam. It uses two partial diffential equations, wherein q is the load:

> PDE1 := kappa*G*A*(diff(y(x, t), x, x)-(diff(theta(x, t), x)))-rho*A*(diff(y(x, t), t, t))-q;

> PDE2 := E*J*(diff(theta(x, t), x, x))+kappa*G*A*(diff(y(x, t), x)-theta(x, t))-rho*J*(diff(theta(y, x), t, t));

The boundary conditions are that in the corners the moments (derative of theta...

Hello,

I am trying to add an if statement to maple code for example if U(tk) less or equal to 4 then 
the initial condition=0 else the initial condition=value .
 
I am getting this error:
Error, cannot determine if this expression is true or false: U(365)

restart;

 k := 0; B[1] := 0.001/365; B[2] :=0.002/365:

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