Hi everybody,

is it possible to define an homokinetic joint in MapleSim for multibody modeling? How can I do that?

thanks.

In brief the problem can be stated as follows:

Given dependent variables Q_i i=1,...,N and independent variables x_i, y_i, and z_i i=1,...,N

which are related via the following system of N linear equations with parameters P₁, P₂ and P₃ :

Q_i = P₁x_i+P₂y_i+P₃z_i   i=1,...,N

How to find the optimal values of  P₁, P₂ and P₃ which satisfy the above system of linear equations subject to the following constraints:

P_i>=0   i=1,2,3

and  P₁>=P₂P₃

 Without the requirement of P₁>=P₂P_3, the problem can be solved with the Non-negative Least Squares Method of Lawson and Hanson.  But with this additional constraint, I am stuck.  

Your suggestions are welcome.

I would like to implement a rule for typeseting delayDotProduct in latex exports (in which this expressions appears in plain form). It corresponds to dot products of vectors/matrices with the "." operator. I tried to define 

`latex/Typesetting:-delayDotProduct`:=proc(f1,f2,f3)
sprintf("{ {%s}{%s} }",cat(`latex/print`(f1)),cat(`latex/print`(f2)))
end proc:

which does not do the job. 

Edit:

A related question: How can I make

D[1,1](x)(t)

produce x''(t) in latex output?

I'd like to plot the following inequalities:

sqrt(x)<=1/sqrt(2)

1/sqrt(2)<sqrt(x)<=1/sqrt(2)

Hey!

I have this MATLAB script, but as I work in Maple, I'll need to translate it to Maple. 
I know how to define symbols and functions, but I don't know which Maple commands to use, of if it needs to be done in another way, so the problem is translating from " dZ = [dx; dy; ax; ay; dm];" and down.

Any help would truly be greatly appreciated! Thank you!  

This is the script:

function dZ = meteor_step(~, Z)

  P = 1.2; % initial atmospheric pressure
  H = 1.39E-4; % scale height of atm pressure
  E = 8.11131859E6; % evaporation energy
  D = 1; % drag constant
  G = 9.814; % acceleration due to gravity
  PM = 3.3E3; % density of the meteor
  
  S = 3.986E14; % standard gravitational parameter of Earth (G*M)
  R = 6.3674447E6; % radius of the Earth (meters)

  x = Z(1);  
  y = Z(2);
  dx = Z(3);
  dy = Z(4);
  m = Z(5);
  
  atm = P*exp(-y*H);

  v = sqrt(dx^2+dy^2);

  area = pi * ( (3*m)/(4*PM) )^(2/3);

  dist = sqrt(x^2+y^2);
  Gv = -9.8;

  accel = -(D*atm*area)/m*v;
  ax = accel * dx;
  ay = accel * dy + Gv;
  

  dm = -(atm*v^3*area)/(2*E);
  
  dZ = [dx; dy; ax; ay; dm];
  
end

[t, R] = ode45(@meteor_step, [0 250], [0, 100000, 100, -300, 25]);

x = R(:,1);
y = R(:,2);

dx = R(:,3);
dy = R(:,4);

v = (dx.^2+dy.^2).^(1/2);

m = R(:,5);

figure(1);
plot(t, y);
  title('Meteor Kinematics: Height vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Height (m)');

figure(2);
plot(x, y);
  title('Meteor Kinematics: Horizontal vs Vertical Position');
  xlabel('Horizontal (m)');
  ylabel('Vertical (m)');

figure(3);
plot(t, v);
  title('Meteor Kinematics: Speed vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Absolute speed (m/s)');

figure(4);
plot(t, m);
  title('Meteor Kinematics: Mass vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Mass (kg)');

  
figure(5);
plot(t, dy);
  title('Vertical Velocity vs Time');
  xlabel('Time elapsed (s)');
  ylabel('Vertical velocity (m/s)');

temp = abs(y - 52900);
[~, index] = min(temp);
  
t(index)
dx(index)/1000
dy(index)/1000

I've got a worksheet in which I have invested many hours of CPU execution time and if the computer goes down, or Maple fails for some reason, I'll lose it all.

If this happens I would like to be able to continue the calculation from where I left off.

By saving the worksheet periodically, I can save all the commands, but not the results, so if I have to restart, I'll have to wait many hours before the worksheet catches up to where it left off.

In ancient versions of Maple, you used to be able to save an executed worksheet including results (I sort of remember that you wrote a file with the extension ".M")  but the new help pages say that is now different from what it used to be. Obviously I can "save" individual symbols to a file, but for a complicated worksheet  that gets complicated.

I've read about "maplet" files, but that doesn't seem to fill the bill either.

So, is there any simple way to save a worksheet so you can continue seamlessly from where you left off after a crash, with all the previous results intact?

I have the following situation:

HB:=Bend(L,a,n);

Bend is a proc, that returns a Record with info based on its parameters. I would like to get access to the name I assign to (i.e. HB) in the proc. Any chance?

Mac Dude

PS: I can of course kludge things by adding an argument to the proc Bend. But I'd like to avoid that.

Hi,

I'm trying to solve the following differential equation numerically with dsolve:

but dsolve gives me this error:

> res := dsolve(DGL, numeric, parameters = [y0, A, B, C, E]);
Error, (in DEtools/convertsys) unable to convert to an explicit first-order system

I think the problem is that I use the wrong solver. Does Maple provide a solver which is capable of solving this kind of equations (nonlinear ODE)?

Thanks in advance!

hello , to solve a differential euqations , maple gave me this error. please help me.

TG.mw

Hello, 

I`m new with the Physics package. I have a Hamiltonian in a lattice written in terms of creation and annihilation operators. The Question is, How can I label a Creation and an Annihiliation operator for each site in the Lattice. WIth this, I can compute mean values and other stuffs associated with the Hamiltonian.

Many thanks in advance

Hi,

  Excuse me, I tried to substract in a series expansion. It works for Taylor-type expansion, but not Laurent-type ones

*********

ffff:=1/(t-3);
ggg:=taylor(ffff,t=infinity,3);
coeff(ggg,t,-1);

ffff:=exp(t);
ggg:=taylor(ffff,t=0,3);
coeff(ggg,t,1);

*********

Maple gives me

Error, unable to compute coeff

1

. My question is, why "coeff" does not work in the first case? how to make it work? Though I can copy the expansion part, assign it to another variable, and "coeff" will work

Excuse me,

  I have the following input

***

fff:=x1^k;
int(fff,x1=0..x2);

***

I would like to obtain

1/(k+1)* (x2^(k+1)), k<>-1

but maple gives me just the same integral. Is there any way to get the expression?

Thank you!

I am trying to make a plot3d on my Surface Pro  3 running Windows8.1.

The plot looks like a ghost.  Pale grey.  It looked nice and colourful when I executed the same command on an older computer a few hours ago.  (I know it was exactly the same command because I saved the file on my old computer and then opened in on the Surface Pro 3)

Is there a way to fix this?

plot3d(-x^2+y^2-3*x+2*y+100, x = -5 .. 8, y = -5 .. 5, transparency = 0, lightmodel = light1, glossiness = 1, filled = true, style = wireframeopaque, shading = zhue, view = [-5 .. 10, -5 .. 8, 0 .. 150]);

 OOPS!  Now the problem has corrected itself.  

I'm getting worried about all the weird things Maple is doing on this Surface Pro 3.  I'm trying to make up a final exam tonight (the exam is tomorrow).

I have downloaded MaplePlayer on my iPad.   I see that it comes with a number of "pre-recorded" programs that it can run.  Is there a way to have it run a Maple worksheet that I have written?   If so, how do I use this app to open an existing worksheet? 

Also, are there any plans for this app on the Android platform any time soon?

I have written a program and I would like to embed a check near the beginning to see if input data was entered correctly.  I have written an "if statement" to check on this and I would like the program to stop execution at this point if the "if statement" criteria are met.   I get an error saying that this command is disabled.   I have tried "stop", "end" and "quit," as I understand that they are all the same.