I have solved a partial differential equation numerically using PDSolve and now I would like to visualise what is happening in my system. I have tried to watch some tutorials on how to do so, but these only explain how to do it when you have a function, rather than a set of numerical results. Also, the animate function of pdsolve only gives me a 2-D plot, however, I would like a 3-D animation. Could anyone give me any tips on how to do so

 

Thanks in advance.

Can anyone please write a procedure to multiply 2 matrices in maple ??
(  it has to be a written procedure so without using maple built in multiplication matrices function )
thankssss

Hi, all, Is there a way to compare two lists containing polynomials to check whether they are equal? Thanks Gepo

hello all,

i attach the worksheet. It shows an 'invalid object' error. i really cant figure out what is wrong. can someone have a look please?also, is there any way to get maple to point me to where it finds errors?

View 16354_take1.mw on MapleNet or Download 16354_take1.mw
View file details

 

Lovinash

Dear All,

I wonder if anyone could perhaps offer some advice concerning evaluation of the following definite integral in closed form.  The integral is defined in the principal value sense and arises in a problem involving integration over an ellipse with the axes given by a and b. The command int(...) (see below) used in Maple 13 does not seem to deliver any result in finite time. Thanks a lot!  Bartek
 

I am using NLPSolve to maximize the the sum of pij*LN(pij) over i and j subject to linear boundary conditions. I notice the help page for NLPSolve says it finds a global max if the objective function is convex. I expect Maple can figure out if x*LN(x) is convex, but I had to define f(x)= xLN(x) if x<>0 and f(0)=0. Does Maple determine whether this function is convex? How? Is there a place for me to declare it convex? Or does the algorithm just al;ways work ( to find a global max) if the objective is convex?

My coursemate and I tried to solve a differential equation using the following code:

>PDE := diff(Sigma(R, t), t) = 3*(diff(R^.5*(diff(Sigma(R, t)*R^.5, R)), R))/R;
>IBC := {Sigma(0, t) = 10, Sigma(R, 0) = 0};
>pds := pdsolve(PDE, IBC, numeric, Sigma(t, R), indepvars() = (R, t), time = t, range = 0 .. infinity)
%
Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 2, got 1

Hello

I need a procedure, or command, which will identify the unique sets which sum to 1 (from a permuted list).

by way of explanation:

> with(combinat);

>A := permute([1, 1, 0, 0, 0, 0, 0, 0], 8);

[[1, 1, 0, 0, 0, 0, 0, 0], [1, 0, 1, 0, 0, 0, 0, 0], [1, 0, 0, 1, 0, 0, 0, 0],

  [1, 0, 0, 0, 1, 0, 0, 0], [1, 0, 0, 0, 0, 1, 0, 0],

  [1, 0, 0, 0, 0, 0, 1, 0], [1, 0, 0, 0, 0, 0, 0, 1],

  [0, 1, 1, 0, 0, 0, 0, 0], [0, 1, 0, 1, 0, 0, 0, 0],

Hi,

I want to make a 3D plot of the following function of alpha and beta:

Hi, Solving a non linear eq. system I got the solution posted below. Here I only show one solution for a certain value of "a2", but in fact I got n rigs as n values of "a2" I am interested.

The Question is:How can I isolate a value from this solution,for instance to create a vector with the several "P" results for each solution given.Thanks,JPA

With a Mac using Firefox you would hold command + alt and left or right arrows to change between tabs.

 

How would you do this in Maple? Does such a feature exist?

Hello all,

I'm running into a bit of a problem finding an efficient way of forming the expansion coefficient for an eigenfunction expansion. The way I currently have it coded works, and it doesn't take terribly long (about 30 seconds or so). However, I have to run a lot of different evaluations, so all that time begins to add up. In addition, the memory usage balloons until I am pretty much frozen and unable to complete the calculations.

So, here's the block of code that's causing me problems:

for p to P do

for q to Q do

Hi, all, I have a list of polynomials and then I want to get polynomials which include given variables. How can I do this? For example, I have a list: L:=[a+b+c,x+ab+d^3,y+c]; and I am only interested in polynomials which include varaibles "a", "b", "c", which is "a+b+c". Which command can implement this? thanks Gepo

Hi, I'm working on the Smoluchowski equation (essentially the diffusion eqn with an extra derivative) diff(u(x,t),t)=k*diff(u(x,t),x)+D*diff(u(x,t),x,x) k is piecewise so the function has to be solved numerically, the boundary values are specified u(0,t)=u(1,t)=0 but i need the derivative at the boundaries D[1](0,t) and D[1](1,t). It seems to be simple to evaluate a numeric derivative of an ODE but I can't see how to do it for a PDE. Any help welcome, even some sort of brute force method if necessary. Thanks, Ryan

How do i convert a curve into its data points i.e. how can  i get the points from a curve.

Thanks