Hi,

It should be simple, ...but results are wrong,
Please see for time above 4 hours.

What's wrong?

wzel

HT_one_layer_barrie.mw

Hello,

I try to calculate a big matrix product which is used after for the resolution of a differential system.

In the link below, you have the matrix product which causes me trouble.

http://dl.free.fr/p8fP9XqWn 

The matrix are composed with trigonometric functions.

I think that the problem is due to the fact that Maple tries to determine a analytical solution.

But, for my use, i only need a numerical result that i can use after for solving my differential system.

Have you some ideas in order to make this matrix product? 

Thank a lot

Dear All,

This's my first post on this website; I'm hoping I can get some useful ideas on how to approach the numerical solution for system of PDE's, with initial and boundary conditions.  I'm using Maple 15.

The PDE is,

pde:={diff(p(r,t),r)-v(r,t)^2/r-g1=0,diff(v(r,t),r$2)+beta*diff(diff(v(r,t),r$2),t)-diff(v(r,t),r)*(1/r)-(beta/r)*diff(diff(v(r,t),r),t) +diff(v(r,t),t)*(beta/r^2)+v(r,t)/r^2+(2/r + C*diff(p(r,t),r))*(diff(v(r,t),r)-v(r,t)/r+beta*diff(diff(v(r,t),r),t)- 1/r * beta*diff(v(r,t),t)-Re*(1+lambda)*exp(1-p(r,t))*diff(v(r,t),t)-(1+lambda)*exp(1-p(r,t))*g2=0};

The initial and boundary conditions are,

IBC:={p(1,t)=k,v(r,0)=0,v(1,t)=sint,v(2,t)=0}

I'm trying to solve and plot,

sol:=pdsolve(pde,IBC,numeric,time=t,range=0..1)

but i'm getting an error; (in pdsolve/numeric/match_pdes_bcs) cannot handle systems with multiple pde describing the time dependence of the same dependent variable or having no time dependence

Regards

J. Lee

f := Diff(u(t),t$2)+Diff(u(t),t)+u(t)+x(t);

after indicate to extract u(t), should output Diff(u(t),t$2)+Diff(u(t),t)+u(t)

after indicate to extract x(t), should output x(t)

@fairuzalwani 

Hi! I have difficulties in plotting my proc. I have this proc,

> Orbit:=proc(Map,ic,Nit)
local orbit,z,t:
orbit:=array(0..N):
z:=ic:
orbit[0]:=z:
for t to Nit while (z<>ic) or t=1 do
z:=Map(z);
orbit[t]:=z;
od:
return [seq(orbit[t],t=1..N)];
end;

##If I run it, let say

>Orbit(F, [1, 1], 15);

##the output would be something like this:

[[1, 1], [3, 0], [-1, -1], [1, 0], [-3, -1], [-1, 0], [7, 1], [9, 0], [5, -1], [-5, -2], [-9, -1], [-7, 0], orbit[13], orbit[14], orbit[15]] 

##since it already found the periodic point. But, I need to include my initial condition z:=ic to be able to plot the graph but I do not have idea on how to do it. Please help. Should I make changes in my proc or in my plot structure?

Thank you in advance!

hello .

i don't know how to change matrix to string?
for example
to become ["00101111010","00001001111"]??
how can do that?
if matrix bigger containts, how i do that??

I have a function d(x,y,z) that returns the appropriate standard basis vector in 8 dimensions, e.g. d(0,0,0) is the column vector <1,0,0,0,0,0,0,0> and d(0,1,0) is <0,0,1,0,0,0,0,0>. Now, to make a sum over all possible elements, I have tried a sum like this:
sum(sum(sum(a_(i,j,k)*d(i, j, k), k = 0 .. 1), j = 0 .. 1), i = 0 .. 1)

with a_(i,j,k) simply being some coefficient that I want to place in the appropriate position. Basically, I would like to get a column vector: <a_000, a_001, a_010, a_011, a_100, a_101, a_110, a_111>, but the result of the sum above is: <0, 0, 0, 0, 0, 0, 0, a_000 + a_001 + a_010 + a_011 + a_100 + a_101 + a_110 + a_111> instead.

This completely baffles me - it looks like the 'a' coefficients are given the correct indices, but d() is always called with d(1,1,1). Can anyone help? Thank you.

I have Maple 15 and I am transferring it to a different computer but I cannot find the download link anywhere. Where would I find it? Thank you!

Hello, i am working on creating a smooth curve from my data points: [0.2e-1, .158], [0.2e-1, .159], [0.3e-1, .161], [0.3e-1, .164], [0.3e-1, .166], [0.4e-1, .169], [0.6e-1, .173], [0.8e-1, .178], [.1, .185], [.11, .187], [.14, .193], [.19, .2], [.28, .21], [.38, .223], [.44, .233], [.58, .244], [.82, .256], [1.4, .278], [1.71, .281], [1.78, .282], [1.78, .282], [1.81, .282]

however, I am not sure how to to create the smooth curve formula for said data points. I tried using polycurve, but it didn't spit out any equations.

If f(n)=a^n+b^n+c^n   and f(1)=1,f(2)=2,f(3)=3 ,n=1,2,3,.... Find f(5) ?

As of today it does no longer properly load using Firefox, but using IE works

Hi! I am a newbie in Maple. For several days trying to read help but no luck. Search here for "solve tensor equation" does not help either.

There are tensor package and physics package but in both helps i have not found how to solve simple tensor equation A_ijmnB^_mnkl=C_ij^kl. Let's say A and C i create as analytical arrays and then create tensors on the base of them (not Arrays - for some reason the tensor cannot be created on the base of Arrow...

Hello,

I would like to plot z(x(t)) with the odeplot function.

For the moment, i manage to plot x(t) and z(t).

But i don't manage to plot z(x(t)) ?

My last code lign is wrong.

Can you help me for this plotting ?

Thanks a lot

Here my code :

M:=1;                               

1l:=1;

g:=9.81; 

sys:=diff(z(t),t,t)=-1/z(t)*diff(x(t),t)^2-1/z(t)*diff(z(t),t)^2-x(t)/z(t)*diff(x(t),t,t),M*(-l^2/(x(t)*z(t)))*diff(x(t),t,t)=M*g-M*(-1/z(t)*diff(x(t),t)^2-1/z(t)*diff(z(t),t)^2);  

Cinit:=D(x)(0)=0,x(0)=0.99999999,D(z)(0)=0,z(0)=sqrt(l^2-0.99999999^2); D(x)(0) = 0, x(0) = 0.99999999, D(z)(0) = 0, z(0) = 0.0001414213562

sol:=dsolve({sys,Cinit},numeric);

tx:=odeplot(sol,[t,x(t)],0..10,numpoints=200,color=blue,legend="x"):display(tx);

 tz:=odeplot(sol,[t,z(t)],0..10,numpoints=200,color=blue,legend="z"):display(tz); 

txz:=odeplot(sol,[x(t),z(x(t))],0..10,numpoints=200,color=blue,legend="z"):display(tz);(x)