Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Hello
    In this example, we have the KdV equation    
         t] - 6 uux] + xxx] = 0                
    I would like to find the Lax pair for the KdV equation, which are    
               Lψ=λψ                
               ψ[t] = Mψ                
        
              Lt+ML-LM = 0  called a compatibility condition               
    So, I will start from this purpose    
    Then we will assume M in the form   
    will assume M in the form   
              M := a3*Dx^3+a^2+a1*Dx+a0              
    thenb using M and L in the for L[tL-LM = 0can find   
      Dx^5+( ) Dx^4+( ) Dx^3+( ) Dx^2+( ) Dx+( )=0              
    then wean find a_i =0,1,2,3   
  In the following maple code to do that 
  my question is    
   .How I canoue the soluo get a_i2,3 usinmaple code  
    any maple packge to find Lax pair for PDE -  


 

restart; with(DEtools); with(PDEtools)

     in this exampile we have KdV equation

      u[t]-6*uu[x]+u[xxx] = 0

    I would likeind the Lax pair for the KdV equation, which are

       Lψ=λψ

    psi[t] = M*psi

   where``

    L[t]+ML-LM = 0    called  apatibility  condition

    So, I  will start this purpose

     L:=-Dx^2+u;

    then we will assume M the m

    Ma3*Dx^3+a2*Dx^2+Dx+a0

    then busing in the form L[t]+ML-LM = 0 can find

  ( ) Dx^5+( ) Dx^4+( ) Dx^3+( ) Dx^2+( ) Dx+( )=0

 then we can find a_i ;i=,2,3

  

the fllowile code to

 my queion is ;

  1) How I can continue the solution  to get a_i ;i=0,1,2,3 using maple code  ?

  2) isir any maple packge to find  Lax pair for PDE ?

 

alias(u = u(x, t)); declare(u(x, t)); alias(a3 = a3(x, t)); declare(a3(x, t)); alias(a2 = a2(x, t)); declare(a2(x, t)); alias(a1 = a1(x, t)); declare(a1(x, t)); alias(a0 = a0(x, t)); declare(a0(x, t))

u

 

` u`(x, t)*`will now be displayed as`*u

 

u, a3

 

` a3`(x, t)*`will now be displayed as`*a3

 

u, a3, a2

 

` a2`(x, t)*`will now be displayed as`*a2

 

u, a3, a2, a1

 

` a1`(x, t)*`will now be displayed as`*a1

 

u, a3, a2, a1, a0

 

` a0`(x, t)*`will now be displayed as`*a0

(1)

_Envdiffopdomain := [Dx, x]

[Dx, x]

(2)

L := -Dx^2+u

-Dx^2+u

(3)

M := Dx^3*a3+Dx^2*a2+Dx*a1+a0

a3*Dx^3+a2*Dx^2+a1*Dx+a0

(4)

 

 

 

LM := expand(mult(L, M))

-a3*Dx^5-2*Dx^4*(diff(a3, x))-a2*Dx^4+Dx^3*u*a3-Dx^3*(diff(diff(a3, x), x))-2*Dx^3*(diff(a2, x))-Dx^3*a1+Dx^2*u*a2-Dx^2*(diff(diff(a2, x), x))-2*Dx^2*(diff(a1, x))-Dx^2*a0+Dx*u*a1-Dx*(diff(diff(a1, x), x))-2*Dx*(diff(a0, x))+u*a0-(diff(diff(a0, x), x))

(5)

ML := expand(mult(M, L))

-a3*Dx^5-a2*Dx^4+Dx^3*u*a3-Dx^3*a1+3*Dx^2*a3*(diff(u, x))+Dx^2*u*a2-Dx^2*a0+3*Dx*a3*(diff(diff(u, x), x))+2*Dx*a2*(diff(u, x))+Dx*u*a1+a3*(diff(diff(diff(u, x), x), x))+a2*(diff(diff(u, x), x))+a1*(diff(u, x))+u*a0

(6)

Commutator := simplify(ML-LM)

a3*(diff(diff(diff(u, x), x), x))+(3*Dx*a3+a2)*(diff(diff(u, x), x))+diff(diff(a0, x), x)+Dx*(diff(diff(a1, x), x))+Dx^2*(diff(diff(a2, x), x))+Dx^3*(diff(diff(a3, x), x))+(3*Dx^2*a3+2*Dx*a2+a1)*(diff(u, x))+2*Dx^4*(diff(a3, x))+2*Dx^3*(diff(a2, x))+2*Dx^2*(diff(a1, x))+2*Dx*(diff(a0, x))

(7)

sol := diff(L, t)-Commutator = 0

diff(u, t)-a3*(diff(diff(diff(u, x), x), x))-(3*Dx*a3+a2)*(diff(diff(u, x), x))-(diff(diff(a0, x), x))-Dx*(diff(diff(a1, x), x))-Dx^2*(diff(diff(a2, x), x))-Dx^3*(diff(diff(a3, x), x))-(3*Dx^2*a3+2*Dx*a2+a1)*(diff(u, x))-2*Dx^4*(diff(a3, x))-2*Dx^3*(diff(a2, x))-2*Dx^2*(diff(a1, x))-2*Dx*(diff(a0, x)) = 0

(8)

collect(sol, [Dx, x])

-2*Dx^4*(diff(a3, x))+(-(diff(diff(a3, x), x))-2*(diff(a2, x)))*Dx^3+(-3*a3*(diff(u, x))-(diff(diff(a2, x), x))-2*(diff(a1, x)))*Dx^2+(-2*a2*(diff(u, x))-3*a3*(diff(diff(u, x), x))-(diff(diff(a1, x), x))-2*(diff(a0, x)))*Dx-a1*(diff(u, x))-a2*(diff(diff(u, x), x))-a3*(diff(diff(diff(u, x), x), x))-(diff(diff(a0, x), x))+diff(u, t) = 0

(9)

 

 

 

 

``

NULL


 

Download find_lax_pair.mw

Imagine a brachistochrone shaped path made of a frictionless flexible metal strip which reacts to the force of a weighty sliding object.

Depending on its flexibility and the object's mass, what would be the strip's initial shape for fastest descent between its top and bottom? How would its shape change during the object's descent?

Perhaps an aircraft emergency escape slide or the fastest path for a slalom skier exemplify this kind of situation.

I want to define the co-ordianates (phi, PI, ....)  as functions of some variable eg:- x,y.

 

Hi everyone,

When my cursor is on an output, the paragraph style changes to 2D Output, as it most likely should. When I then go to a new executable line, it takes forever for all of my expressions to "light up" (meaning that it takes a while for me to be able to use them), and it takes forever for the paragraph to go from 2D Output to 2D Math.

I sadly don't remember when this happened, or what might have caused it, but if any of have any suggestions or answers, I'd greatly appreciate it.

 

Thanks for listening,

A confused highschool student.

I was playing with some of the geometry plotting in maple for fun(I rarely use it) and came up with an IFS like system. While I'm sure maple sucks for IFS it is somewhat easy to do. I was just using rectangles though.

Is there any way though to modify a shape using a transform such as a complex map? Not just the vertices but the edges too.

 

Also, is there any way to do a complex map in some easy way? e.g., "paint the geometry on to a texture" and then map it with a complex plot. Usually one just uses a pixel coloring map and maps that, which would be fine for playing around but I'd like to have more control.

 

Basically draw something on a plot(geometry, functions, image, etc), transform them in some interesting way(e.g., complex map) and then IFS them to get interesting visuals.

 

I realize one can do this in maple by turning the edges in to curves and all that mess but I'd like to avoid that since maple is not really good at it anyways(would probably end up very slow).

 

I teach high school IB Math.

I want to find someone who can take problems I have created and enter them into Maple (problem and solution) so I can use those in my classroom.

I can keep up with the new stuff I create, but I have almost 20 years of accumulated material I'd like to move into Maple.

 

Does anyone know where I can find someone to enter the problem and solution so that it is proved out in Maple? Maybe an existing college student using Maple at their school for math, engineering, or education? I am willing to pay them, it is just locating them that is a problem.

 

Even if you know a site for maple contractor types, that would be helpful.

 

Thanks a ton!

 

Robert

Hi!

There is a (relatively) known software code (written in C), called ." GKLS-generator" or "GKLS" to generate, according to certain user paramenters, optimization test functions. The code is available for free at the web

http://wwwinfo.deis.unical.it/%7Eyaro/GKLS.html

The download with the files of the GKLS is the following:  download

I would like to write this code in Maple. In the attached zip there is a PDF explaining how to build these functions. For now, I tried the follwoing Maple code GKLS_v4.mw

I think I'm doing something wrong, since the drawing generated by the attached Maple does not look much like the PDF in the attached zip (Fig. 1 of page 8).

Please, Can you help me with this?

Many thanks in advance for your comments.

 

 

Dear Users!

Hope you would be fine with everything. I want the simpliest for of the following expression in two step:

diff(U(X, Y, Z, tau), tau)+U(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), X))+V(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), Y))+W(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), Z))+u[delta]*lambda[1]*(diff(U(X, Y, Z, tau), tau, tau))/L[delta]+u[delta]*lambda[1]*(diff(U(X, Y, Z, tau), tau))*(diff(U(X, Y, Z, tau), X))/L[delta]+u[delta]*lambda[1]*U(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), tau, X))/L[delta]+u[delta]*lambda[1]*(diff(V(X, Y, Z, tau), tau))*(diff(U(X, Y, Z, tau), Y))/L[delta]+u[delta]*lambda[1]*V(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), tau, Y))/L[delta]+u[delta]*lambda[1]*(diff(W(X, Y, Z, tau), tau))*(diff(U(X, Y, Z, tau), Z))/L[delta]+u[delta]*lambda[1]*W(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), tau, Z))/L[delta];
Step 1:
diff(U(X, Y, Z, tau), tau)+U(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), X))+V(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), Y))+W(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), Z))+u[delta]*lambda[1]*(diff(diff(U(X, Y, Z, tau), tau)+U(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), X))+V(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), Y))+W(X, Y, Z, tau)*(diff(U(X, Y, Z, tau), Z)), tau))/L[delta];
Step 2: (final form I need)
(1+(u[delta] lambda[1])/(L[delta]) (∂)/(∂tau)) ((∂)/(∂tau) U(X,Y,Z,tau)+U(X,Y,Z,tau) ((∂)/(∂X) U(X,Y,Z,tau))+V(X,Y,Z,tau) ((∂)/(∂Y) U(X,Y,Z,tau))+W(X,Y,Z,tau) ((∂)/(∂Z) U(X,Y,Z,tau)));
I'm waiting for your response.
Special request:
@acer @Carl Love @Kitonum @Preben Alsholm


How do I remove these unwanted trailing zeros from my plot ? I have tried setting striptrailing=true from the Tyesetting package but no difference. Thanks

 

Hi

I would like to use  the Liebniz notation that someone from the technical support posted here
Writing Derivatives at a Point Using Leibniz Notation
to display a formula that is not just a partial derivative but a more complex expression invoking partial derivatives. 
Typically an expression like this one:

2*(Diff(f(mu__1, mu__2), mu__1))^2*lambda__1^2-(Diff(f(mu__1, mu__2), mu__1))^2*mu__1^2+2*(Diff(f(mu__1, mu__2), mu__2))^2*lambda__2^2-(Diff(f(mu__1, mu__2), mu__2))^2*mu__2^2+2*(Diff(f(mu__1, mu__2), mu__1))*(Diff(f(mu__1, mu__2), mu__2))*lambda__1*lambda__2-2*(Diff(f(mu__1, mu__2), mu__1))*mu__1*(Diff(f(mu__1, mu__2), mu__2))*mu__2

Could anyone help me to do this?
Thanks in advance

(PS: I'm still using Maple 2015.2)

Can I get to know how to interface maple with gnu plot. Thank you.

This must be so complicated process to describe the exact mechanism in human or animals ... and there are many reserchs on web for this subject ! Not expected Large answer !

By this way i am just curious to know by support of signal processing methods available in maple we can model a very basic vibrator as larynx and variable duct (what kind of filter we can call ?) or cavity that play the role of tongue or lips for changing of main stream to made various phonemes or frequencies

Here is a movie that show the section of human vocal system :

Anatomy

I found that while using maple gui cases of corruption, stuck while typing etc. Hope this problem will get solved in coming version

Need the code of the following:

 

h is the step size could be 0.1 or 0.01 etc

Dear experts

I am trying to study linear version of the Navier-Stokes (NS) equation. I define NS equations in a way suggested in this page

restart;

with(PDEtools): with(Student[VectorCalculus]):

SetCoordinates(cartesian[x,y,z]):

V:= VectorField(< v[1](x,z,t),0,v[3](x,z,t)>);

NavierStokes:= diff(V,t) - nu*Laplacian(V) +1/rho* Gradient(p(x,z,t)) - VectorField(< 0,0,-g>)=0;

the velocity components are intriduced as following

v[1]:=(x,z,t)->diff(f(z),z)*exp(I*k*x+(-1)*I*omega*t);

v[2]:=(x,z,t)->0;

v[3]:=(x,z,t)->(-1)*I*k*f(z)*exp(I*k*x+(-1)*I*omega*t);

So the problem is 2D model so that v[1] and v[3] satisfy incompresibility condition. It is clear that substituting velocity components into NS leads to differential equations for f(z). The general form of f(z) is

f(z) = a1*cosh(k*z)+a2*sinh(k*z)+a3*cosh(kappa*z)+a4*sinh(kappa*z).

my problems are

1) apply v[1], v[3] and find f(z) with Maple. then apply boundary conditions to find coeffs a[i] with Maple

2) In addition, Substituting the f(z) into BCs leads to a linear homogeneous system of equations for the coefficients. The vanishing of the determinant of this system which is the condition for the existence of a nontrivial solution is interested. How can I do that?

3) f(z) is for the case that the bottom is z=0 and surface is z=h. in my case bottom is z=-h and surface is z=0. how to do this in the solution. I dont know how to apply it.

4) calculate pressure

this file is what I did.

NSE.mw

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