Items tagged with nonlinear nonlinear Tagged Items Feed

Hi:

i will solve the five nonlinear coupled odes with maple in least time,can evey body help me?

eq1:= -3515.175096*Pi*q[1](T)*q[4](T)-3515.175096*Pi*q[1](T)*q[5](T)-2650.168890*Pi^2*q[3](T)*q[1](T)-9.871794877*10^7*q[2](T)*Pi+.5622514683*(diff(q[1](T), T, T))+1.893468706*q[1](T)^3*Pi^4+2.507772708*10^5*q[1](T)*Pi^2=0

eq2:= 496.9066665*q[2](T)*Pi^2-380.5288665*q[4](T)*Pi-62694.31768*Pi*q[1](T)+380.5288665*q[5](T)*Pi+0.3570776400e-3*(diff(q[2](T), T, T))+2.467948718*10^7*q[2](T)=0

eq3:= 2650.168888*q[1](T)^2*Pi^2+7.824250847*10^5*q[3](T)*Pi^2+1.037806000*10^6*q[5](T)*Pi+.5622514682*(diff(q[3](T), T, T))+1.037806000*10^6*q[4](T)*Pi=0

eq4:= 63661.97724-241.8620273*q[1](T)*(diff(q[1](T), T))-6.792272727*10^6*(diff(q[4](T), T))-5191.348749*q[4](T)-5191.348749*q[5](T)+71406.36133*(diff(q[3](T), T))-6.792272727*10^6*(diff(q[5](T), T))=0

eq5:= 70.02817496+2490.500000*(diff(q[5](T), T))-29887.90351*q[4](T)+29887.90351*q[5](T)-2490.500000*(diff(q[4](T), T))-45.34913011*(diff(q[2](T), T))=0

Dear Friends

I have a problem in CPU time in MAPLE.

I write the codes in maple related to the nonlinear heat conduction problem in one dimension by Collocation method, but after 30 minutes no solution has been observed!!!

My codes are for N=4!, i.e., I have 25 equations with 25 unknowns!!!

If MAPLE can not solve this simple system, How can I solve 3 dimensional pdes by N=9,

In this case, I have 1000 equations with 1000 unknowns!!!

please help me and suggest me a fast iterative solver.

I should remark that my problem is stated in this paper

http://www.sciencedirect.com/science/article/pii/S1018364713000025

If there exist any other suitable method, I will be happy to receive any support.

 

With kind regards,

Emran Tohidi.

 

> restart;
> Digits := 20; N := 4; st := time(); u := sum(sum(a[m, n]*x^m*t^n, m = 0 .. N), n = 0 .. N); u := unapply(u, x, t); ut := diff(u(x, t), `$`(t, 1)); ut := unapply(ut, x, t); ku := simplify(1+u(x, t)^2); ku := unapply(ku, x, t); ux := diff(u(x, t), `$`(x, 1)); ux := unapply(ux, x, t); K := ku(x, t)*ux(x, t); K := unapply(K, x, t); Kx := diff(K(x, t), `$`(x, 1)); Kx := unapply(Kx, x, t); f := proc (x, t) options operator, arrow; x*exp(t)*(1-2*exp(2*t)) end proc;
print(`output redirected...`); # input placeholder
> S1 := {seq(u(i/N, 0)-i/N = 0, i = 0 .. N)}; S2 := {seq(u(0, j/N) = 0, j = 1 .. N)}; S3 := {seq(u(1, j/N)+ux(1, j/N)-2*exp(j/N) = 0, j = 1 .. N)}; S4 := {seq(seq(Kx(i/N, j/N)+f(i/N, j/N)-ut(i/N, j/N) = 0, i = 1 .. N-1), j = 1 .. N)}; S := `union`(`union`(`union`(S1, S2), S3), S4); sol := DirectSearch:-SolveEquations([op(S)], tolerances = 10^(-4), evaluationlimit = 1000000);
print(`output redirected...`); # input placeholder
> assign(sol);
%;
> u(x, t);
> CPUTIME := time()-st;
plot3d(u(x, t) - x exp(t), x = 0 .. 1, t = 0 .. 1)

Hi all

In matlab software we have a command namely fmincon which minimizes any linear/nonlinear algebric equations subject to linear/nonlinear constraints.

Now my question is that: what is the same command in maple?or how can we minimize linear/nonlinear function subject to linear/nonlinear constraints in maple?

thanks a lot

Mahmood   Dadkhah

Ph.D Candidate

Applied Mathematics Department

I have the following nonlinear Differential Equation and don't know how to solve.  Can anyone give me any hints on how solvle for E__fd(t).  I don't even know the specific classification (other than nonlinear) of this DE can someone at least give me hint on that. Thanks.

 

.5*(diff(E__fd(t), t)) = -(-.132+.1*e^(.6*E__fd(t)))*E__fd(t)+0.5e-1

 

Thanks,

Melvin

Hello;
        i am wording on fluid dynamics, in which i can up a system of nonlinear partial differential equation with i am suppose to solve using implicit keller box method. i need an asistance on how to implement this in maple.

hi guys i want to solve this equation with maple please help me

 

eq[1]:=0.223569c_1+2.35589c_2*c_1^2+0.002356c_1*c_2^2;

eq[2]:=1.277899c_1*c_3-2.350023c_2*c_3^2+7.5856c_3*c_2^2;

eq[3]:=3.225989c_1^2+-2.35589c_3*c_1^2-7.28356c_3*c_2^3;

 

i want solve those equations with newton method

 

 

I have 2nd order nonlinear ode I try to solve with Runge Kutta 4th order method in maple but all I get from the outcome was 1 and 0.This is the equation:theta_ode1.mw . How do I do it Or how do I write the code to solve it with maple using  Runge Kutta 4th order method?

I have 2nd order nonlinear ode I try to solve with Runge Kutta 4th order method in maple but all I get from the out is 1 and 0.This is the equation: theta_ode.mw . How do I do it Or how do I write the code to solve it with maple using  Runge Kutta 4th order method?

Himmelblau.mwOn the basis of Dragнilev method…Is there anyone interested in the algorithm to reduce the distance between the points of the given constraints? The algorithm is adapted for use in R ^ n. This is an example of its work on the surface:                      f = - (x1 ^ 2 x2-.3) ^ 2 - (x1 x2 ^ 2-.7) ^ 2 - 5;          ...

Hi,

I am trying to solve system of equations as

f(x,y,c)=0

and g(x,y,c)=0, with c as parameter and f and g are nonlinear function in y and c. My friend suggestedme to use continuation method for this in Matlab. So is there any way...

Hello, everyone. I have been messed up by a system of 50 nonlinear parametric equations with 50 unknowns(see the code in the file named nonlinear ). Since I am new to Maple, I don't know whether it is possible to make such a system work out by software. I've tried the SOLVE and FSOLVE command but get no result. Are there any other ways or toolbox for such kind of systems? Is there any typing wrongs in my code? I am sincerely looking forward to  receive any ideas...

Hi, I want to substitute the result from NonlinearFit into formula and plot together with raw data.

I have two files v.txt and i.txt , v stands for voltage, i stands for current, using formulato fit my raw data,

The picture is captured from my screen.

Hello,

Please, i want to resolve a non linear eaquation with Lagrange multiplier with 4 variables.

But it dosen't work.

Can you help me in this.

 

Thank you

Multiplicateur_de_La.mw

Hi Maple users and experts!

I have some systems of non linear equations. Maple's "solve" is often able to give explicit solutions. However, I'm actually not very interested in the solutions but rather in knowing whether or not a unique solution exists. Is there a way to determine this with maple?

Thanks!

- John

I have total nine equations,out of which some are linear and some of them are nonlinear.I am a new user of maple.The nine equations are

c2+vc = .34,

c2+c3 = .519,

t8+c3-c4-vc = .132,

t1+t5-c2+0.0435=0,

t1-t2-c2+c3-1.334*vc = 0,

t2+t6-c3-c4+0.0435+1.334*vc=0,

-112.5*t1+112.5*t5+300*c2^2+1000*vc = 38.25,

112.5*t1-112.5*t2-300*c2^2+300*c3-300*c3^2-2000*vc+23.4 = 0,

-112.8*t8+112.5*t2-112.5*t6+300*c4^2-300*c3+300*c3^2+1000*vc+14.85 = 0

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