Hello, 

For a few days Maple crashs everytime i try to use the command "plot3d()". 

I had'nt this problem befor and I have no idea what the reason could be. It ist irrelevant what Funktion I try to visualize,  the window just get closed evertime.

I hope someone can help me.

Thank you!

Tom

Error, (in PDEtools/NumerDenom) invalid input: `PDEtools/NumerDenom` expects its 1st argument, ee, to be of type algebraic, but received {[(s_j*e^sigma*b^m*`σ_m`*y_i-s_j*e^sigma*beta*`σ_i`+s_j*e^sigma*b_ilo+(1/2)*b^(m+2)*`σ_j`*e^sigma*`σ_m`*y_i-b^2*`σ_j`*e^sigma*beta*`σ_i`+(1/2)*b^2*`σ_j`*e^sigma*b_ilo-(1/2)*b^(2*m)*`σ_m`^2*b_j*e^sigma*y_i+(1/2)*b^m*`σ_m`*b_j*e^sigma*beta*`σ_i`-(1/2)*b^m*`σ_m`*b_j*e^sigma*b_ilo+b_j*(s_ilo+(1/2)*(b^2*`σ_i`-b^m*`σ_m`*beta)*_lo)+b_j*(s_jlo+(1/2)*(b^2*`σ_j`-b^m*`σ_m`*beta)*_lo)+s_i*e^sigma*b^m*`σ_m`*y_j-s_i*e^sigma*be... when I use simplify I have this error. please guide me Saberali

Hi all,

I have a system of nonlinear equations with for equations, 4 variables I want to solve for, and 2 parameters. All of the variables and parameters must be non-negative.

The code I used to try to do this is:

Where eq_i (i = 1, ... , 4) are expression (not equations in themselves). For example, eq₁ is:

 

When I try to run this code I get the following error:

"Error, (in SolveTools:-Inequality:-Piecewise) piecewise takes at least 2 parameters"

 

Can anyone help me how I can make Maple do what I want here? :)

 

Thank you in advance,

JTamas

I am trying to solve the pde:= (d/dt)^2v+(d/dx)^2v+v=0 with initial boundary conditions v=xexp(x^2)

I use pdsolve to get v but I wish to tell pdsolve to use a different numerical method because my output of v is coming out like a step function.

Dear reader,

Have to create digital questions in Mobius on quaternions. Aim is to teach students of robot engineering about rotations besides the matrix rotations. Made some code, it works but very simplistic. I could not load a quarternion-toolbox.

Any suggestions?

# quaternion product
# define two vecotrs p and q:
$p0=range(3,3,1);
$px=range(1,1,1);
$py=range(-2,-2,1);
$pz=range(1,1,1);
$q0=range(2,2,1);
$qx=range(-1,-1,1);
$qy=range(2,2,1);
$qz=range(3,3,1);
$p=maple("Vector([$px,$py,$pz])");
$q=maple("Vector([$qx,$qy,$qz])");
$displayp=maple("printf(MathML:-ExportPresentation($p))");
$displayq=maple("printf(MathML:-ExportPresentation($q))");
# p.q=p0.q0-(p.q)+p0.q+q0.p+p*q
# scalar part
$dot=maple("LinearAlgebra[DotProduct]($p,$q,conjugate=false)");
$scalar_part=$p0*$q0-$dot;
# vector part
$cross=maple("LinearAlgebra[CrossProduct]($p,$q)");
$p0q=maple("LinearAlgebra[MatrixMatrixMultiply]($p0,$q)");
$q0p=maple("LinearAlgebra[MatrixMatrixMultiply]($q0,$p)");
$pq=maple("LinearAlgebra[VectorAdd]($p0q,$q0p)");
$vector_part=maple("LinearAlgebra[VectorAdd]($pq,$cross)");
$displayvector_part=maple("printf(MathML:-ExportPresentation($vector_part))");
# unit vectors
$i=maple("Vector([1,0,0])");
$j=maple("Vector([0,1,0])");
$k=maple("Vector([0,0,1])");
# generate answers
$x=maple("LinearAlgebra[DotProduct]($vector_part,$i)");
$y=maple("LinearAlgebra[DotProduct]($vector_part,$j)");
$z=maple("LinearAlgebra[DotProduct]($vector_part,$k)");
 

Best regards,

Nico Booij

I'm plotting some simple plots such as

plot(frac(x^2/3)*3,x=-5..5, discont=true);

 

Some discontinuities are connected. Using numpoints, resolution, and Digits doesn't help. Sometimes it will produce a plot with no connections but then other times it does. I need a general solution that is simple. Is there any way to refine the quality of discont?

 

discont=[usefdiscont=[bins=35]],

 

I have tried that and it seems to work but I haven't put it through the ringer. Is that all I have?

 

I wrote a code.mw for a numerical method for a PDE. (You can find the numerical method, exact solution and error between them in the code.)

The method depends on parameters k, M, which are any positive integers, and also depends on teta, beta>-1 which are real numbers.

According to the used method,

when k and M increase, we expect that the error (exact-numeric) generally decreases. 

In the code, I selected k=2, M=2, teta=1 and beta=1. And so k=2, M=2, CPU time is low. Error is not bad.

But for k=4, M=3 and also for bigger values of them, CPU time is high. I can' t get the solution.

Question 1: 

I don't know, but it may be possible to simplify the code in order to calculate for k=4, M=4?

Question 2:

I want to find optimal values of teta and beta for minimizing the error between numerical and exact solution, when k=2, M=2, or k=3, M=1 etc.

How can we write a Maple code for finding optimal values of teta and beta?

You can download the code.mw

 

 

Hello, I'm using free 15 day trial Maple 2019.2 on my Macbook (Macos 10.15.3).

I can't work Maple. I enter some inputs (2+3) and press enter. It works. But when I write plot, version(), f, sin.. or something else it didn't works. And no response. When I click enter, nothind happen. What is the problem? Please help me.. 

How do I simplify KdV equation in Maple by using =fxt))xx)?)

 

>     I am by using =2*difffxtxx)     My aim is to get the form     >  >  >  >  >  (1) >  (2) >  (3) >  (4) >  (5) >  >  >  >

 

Download KdV_simplify

Is there lifting function for polynomials or algebra use?

expect input a list univariate polynomial , then output a list of polynomials of two variables.

it should be the reverse operation of projection.

Which library has this function in maple 12 or maple 2015?

I am a beginner of MapleSim. I study the MapleSim User Guide. I follow the Tutor 8:Modeling Hydraulic System. But the following issue occurs, as shown in the picture. I bet I follow the guide carefully.

Also, I find that if I open the User's Guide example,Chapter 6, Analysis of Simple Hydraulic System Network, which is the standard example,I simulate it and it works well. But if I delete the probe, and attach a probe at the same place , selecting same values to measure, and simulate again, it failed, giving the same error description. I need your help,please.

problem_with_Analysis_of_Simple_Hydraulic_Network.msim

 

Hello All,

I have an autonomous system of ordinary nonlinear equations. In order to investigate it near the fixed points, I would like to reduce it to the normal or hyper-normal form. I see in the literature that some authors developed unique algorithms for the very specific differential systems (e.g., the systems with two/three eigenvalues), which is not my case.  

Maybe you know, if Maple has any specific commands that may conduct such type of reduction?

Thanks in advance,

Dmitry

 

 

hi daer 

i am trying to run the following but error came 

acually the boundry conditions are periodic

x=linspace(0,1,50);
t=linspace(0,1,50);
m=0;
eqn=@(x,t,u,dudx)transistorPDE(x,t,u,dudx,C);
ic=@(x)transistorIC(x,C);
sol=pdepe((m,eqn,ic,transistorBC,x,t);
function [c,f,s]=transistorPDE(x,t,u,dudx,C)
a=0.1;
c=1;
f=0;
s=-a*dudx;
end
function u0=transistorIC(x,C)
L=1;
u0=exp(-(x-L/2)^2);
end
function [pl,ql,pr,qr]=transistorBC(xl,ul,xr,ur,t)
pl=ul;
ql=0;
pr=pl;
qr=0;
end
 

 

I’m starting a large project in education for which I can see great potential in the use of the “MapleCloud”.  For many of the students, the ability to see information on their phone is a game-changer. Hence while my students do have access to Maple on their computers, they are more willing to check out a worksheet if they can view it in a browser.

Unfortunately, in the little time that I have started using MapleCloud, and sharing my work with others, numerous issues have arisen. Some examples:
  * the file system is too simplistic and can be overwhelmed easily as I add content;
  * the group sharing system is too limited – one must log on, which is not true for worksheets;
  * the display of the mathematics is sufficiently quirky that it is not easy to read;
  * the hiding of input mathematics appears not to work;
  * plots, animations and the output of the Explore function fails too frequently.

So, my questions:
  1) are you using MapleCloud, and
  2) if so, for what?
  3) And if you are using MapleCloud, do you have similar problems?
  4) Have you developed solutions that you would be willing to share.

If there is no interest, I’ll look in another direction. But if there is sufficient interest, I would hope Maplesoft notices and works to correct and improve. Some of it may be my own failing to understand Maple, but instead of overwhelming MaplePrimes with questions, I would rather converse with similar interested folks.

 

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 -  

 

>       in this exampile we have KdV equation            I would likeind the Lax pair for the KdV equation, which are        Lψ=λψ         where     +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 +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 ?   >  (1) >  (2) >  (3) >  (4) >    >  (5) >  (6) >  (7) >  (8) >  (9)   >    >    >    >  >

 

Download find_lax_pair.mw