Here, I have a 3D map T=(T1,T2,T3) with

T1(x1,x2,x3)=x1*exp(6-2*x1-x2-0.3*x3),

T2(x1,x2,x3)=x2*exp(5-2*x1-2*x2-*x3),

T3(x1,x2,x3)=x3*exp(8-0.2*x1-x2-x3),

How can I use  IterativeMaps:-Attractor obtain the attractor for T.

I am not unfamiliar with the Wolfram syntax but also not very good with it, and there is a particular element in a Mathematica code I have been given which I do not entirely understand how to efficiently write in Maple. The basic idea is to read in a list of expressions from an external file (LIST) and process the non zero elements and assign them to a function (COEF) which can be called later on. Here is the Mathematica exert:

k = 0;
i = 0;
a = b = \[Theta];
Do[k = k + 1; KK = LIST[[k]]; 
  If[KK =!= 0, i = i + 1; ff = Factor[KK]; 
   COEF[x,y, z, l_, m_, n_] = ff], {z, -2, 
   2}, {y, -2, 2}, {x, -2, 2}];

The LIST has the following form and only contains l, m and n and another factor E which is left undefined for now. It does not contain x, y or z. The LIST can contain any number of terms depending on the problem. Here is an example:

LIST={0, 0, 0, 0, 0, 0, 0, a^2 b m (-1 + n) n (a^2 + b^2 - 2 E), ... ,0,0, a^3 n(l+1+m) ... }

So the Do loop cycles through the LIST and extracts out the non zero terms. What I am unsure about is how it is looping over x,y and z when they do not appear in the LIST at all. I assume it is attaching a x,y,z combination to each COEF and they can be called like this:

COEF[0,1,1,0,2,3]

For the instance of when x=0, y=1, z=1, l=0, m=2 n=3. Is this correct? What would be the best way to replicate this in Maple?

- Yeti

i want to solve the system of equation ( 1 )  , (2)  ,  (3)   under the assumation that x , y have the CDF in (4)  ,  (5)
 

Download internet.mw

How do we write code for optimal problem using Pontryagin's maximum principle for simulation.

I want to make the blue output my procedure spits out a another color, and align it to the right, is this even possible? Or something like it?

I basically want to make a Maple procedure that does certain calculations and writes the explanation for each calculation. I do however want Maple to write these explanations as a text field like in a normal Maple worksheet, instead of the blue output in the middle. Is this possible? Or is there any alternative ideas you have that I could try? Would really appreciate any kind of help, thanks.

I have included a transfer function of a 3 degree of freedom system.  There are special loci, aside from s = 0, where the numerator will equate to a REAL scalar value, and the denominator will reduce to a simple product of the individual z roots.  Does anyone know if there is some physical significance, interpretation, or analog to this condition and special loci?untitled.mw

hello, i just try to plot the relation between my outputs (u, and phat) with i from 0 to 10 , but i have aproblem any suggestions? 
 

Download hw_4_structural.mw

Hello everyone,

     I am having trouble trying to solve a system of differential equations. The modeling was made from the equilibrium equations of a pressure vessel. The set of equations is shown below:

     As you see it is a set of two second-order partial differential equations. So, we need four boundary conditions. This one is the first. It means that the left end of the pressure vessel is fixed.

This one is the second boundary condition. It means that the right end of the pressure vessel is free.

This one is the third boundary condition. It means that the inner surface of the pressure vessel is subject to an external load:

At last, we have the fourth boundary condition. It means that the outer surface of the pressure vessel is free.

     The first test I have been trying to do is the static case. In this case, the time terms (the right side of the two equations shown) is zero.

    The maple commands that I am using are the following:

restart; E := 200*10^9; nu := .33; G := E/(2*(1+nu)); RI := 0.254e-1; RO := 2*RI; p := proc (x) options operator, arrow; 50000000 end proc; sys := [E*(nu*(diff(v(x, r), x))/r+nu*(diff(diff(v(x, r), x), r))+(1-nu)*(diff(diff(u(x, r), x), x)))/(-2*nu^2-nu+1)+G*(diff(diff(u(x, r), r), r)+diff(diff(v(x, r), x), r)+(diff(u(x, r), r))/r+(diff(v(x, r), x))/r) = 0, E*((1-nu)*(diff(diff(v(x, r), r), r))+nu*(diff(diff(u(x, r), x), r))+(1-nu)*(diff(v(x, r), r))/r-(1-nu)*v(x, r)/r^2)/(-2*nu^2-nu+1)+G*(diff(diff(u(x, r), r), x)+diff(diff(v(x, r), x), x)) = 0]; BCs := {E*(nu*v(L, r)/r+nu*(D[2](v))(L, r)+(1-nu)*(D[1](u))(L, r))/(-2*nu^2-nu+1) = 0, E*(nu*v(x, RI)/RI+(1-nu)*(D[2](v))(x, RI)+nu*(D[1](u))(x, RI))/(-2*nu^2-nu+1) = -p(x), E*(nu*v(x, RO)/RO+(1-nu)*(D[2](v))(x, RO)+nu*(D[1](u))(x, RO))/(-2*nu^2-nu+1) = 0, u(0, r) = 0}

sol := pdsolve(sys, BCs, numeric)

I am getting the following error:

Error, (in pdsolve/numeric/process_IBCs) initial/boundary conditions must depend upon exactly one of the independent variables: 0.1459531181e12*v(L, r)/r+0.1459531181e12*(D[2](v))(L, r)+0.2963290579e12*(D[1](u))(L, r) = 0

In this case, my boundary conditions do depend on more than one independent variable. How do I proceed?

Thank you in advance,

Pedro Guaraldi

Is there anyone who has seen maple 2017 provide some details about what new features are being introduced. Is there a platform where we can suggest what features we would like to be added or enhanced?

I'm trying to define some multilinear forms to study differential geometry. What I need is only symbolic. My intention is symplify computations involving multilinear forms.

For example, to create an symbolic inner product "g" I used the command "define" like in this post:

http://www.mapleprimes.com/questions/203480-Define-And-Use-Abstract-Linear-Operator

So I tipped:

define(g, orderless, multilinear);

My doubt is: how can I declare that g(x,y) is always scalar?

With it I would simplify things like g(g(z,w)*x,y) = g(z,w)*g(x,y)

In my case, specifically, I type:

v:=(X,Y,Z)->g(Y,Z)*X-g(X,Z)*Y;

r:=(X,Y,Z,W)->g(v(X,Y,Z),W)-g(Y,T)*g(v(X,T,Z),W)+g(X,T)*g(v(Y,T,Z),W);

expand(r(X,Y,Z,W));

and the result is:

g(W,g(Y,Z)*X)-g(W,g(X,Z)*Y)-g(T,Y)*g(W,g(T,Z)*X)+g(T,Y)*g(W,g(X,Z)*T)+g(T,X)*g(W,g(T,Z)*Y)-g(T,X)*g(W,g(Y,Z)*T)

But I would enjoy that it were:

g(Y,Z)*g(W,X)-g(X,Z)*g(W,Y)-g(T,Z)*g(T,Y)*g(W,X)+g(X,Z)*g(T,Y)*g(W,T)+g(T,Z)*g(T,X)*g(W,Y)-g(Y,Z)*g(T,X)*g(W,T)

Is there a way to declare that g(x,y) is always scalar?

Thanks.

I have a problem using dchange when my variable depend on two (or more variables) and I would like to apply the chain rule.

For example, when I use the command

I would expect something like 

But I get an error saying that the number of new variables and transformation equations must be the same.

Any idea how I could solve it? 

Thanls a lot for your help.

i need to solve for u[i+1] as i attached i wrote the equations but i cant get any answers for it, the delta t is 0.1 and i need to go for ten steps, thank you
 

Download hw_4_structural.mw

Greetings,

currently im working on a project in which i basically have to calcuate and plot a little solar system, using newton mechanic. The work is done, but as it appears, the solution simply cannot be true. In the given example you can see that the planets move in more or less straight lines. I presume that the error is somewhere in the solution of the system of differential equations, but i can't see where it is.

I am grateful for every advice.

PlanetenSpacecurve.mw

I m using the follwing commands for ploting the five differnt values of M

with(plots):
SDfd1 := odeplot(dsol[1], [eta, diff(f(eta), eta)], -1 .. 1, color = green, axes = box);
SDfd2 := odeplot(dsol[2], [eta, diff(f(eta), eta)], -1 .. 1, color = red, axes = box);
SDfd3 := odeplot(dsol[3], [eta, diff(f(eta), eta)], -1 .. 1, color = blue, axes = box);
SDfd4 := odeplot(dsol[4], [eta, diff(f(eta), eta)], -1 .. 1, color = black, axes = box);
SDfd5 := odeplot(dsol[5], [eta, diff(f(eta), eta)], -1 .. 1, color = pink, axes = box);
display([SDfd1, SDfd2, SDfd3, SDfd4, SDfd5], labels = ["η", "f ' (η)"],
    labeldirections = [horizontal, vertical], labelfont = [italic, 16], axes = boxed,
    axesfont = [times, 14], thickness = 3);

But i do not want in colors.....i need graph without colors in different styles. how can ? Moreover i need legend which must be in centre of graph or within the box. It must not on left, right ,up or below. can some one help ?