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 am trying to find the root of an equation that involves a procedure and a definite integral (solved numerically). Of course, I don't need the root to be found symbolically, but numerically would be fine. The problem is, I keep getting the error

"Error, (in fsolve) Can't handle expressions with typed procedures"

whenever I try to solve it. Anyone have any ideas? My worksheet is here: Table-1-duplication-mapleprimes.mw 

Hi,

I'm trying to fit some parameters to the data of multiple slightly different experiments.

I've written a function which returns the sums of the error for all experiments.

The function which has to be minimized does the following:

1) Set parameters for the model ODE based on the input parameters

2) calculate the difference (numeric solution of ODE <-> experimentel data)

3) repeat step 1+2 for all experiments

4) return the sum of all differences

The function works as aspected. But when I try to minimize it by calling:

I got an error:

"Error, (in dsolve/numeric/process_parameters) parameter values must evaluate to numeric, got A = A"

For some reason Maple isnt able to set the new parameters of the ODE.

Anyone got an idea how to fix this?

Thanks in advance.

I got a problem with solving a second order ODE. 

The ODE is :

-V(xi)+(1/2)*xi*(diff(V(xi), xi))+(1/4)*(diff(V(xi), xi, xi))=-(1/2)*k2*(diff(H(xi), xi))-k1*n*X/E+1+k2

where k1,k2,n,X,E  all are constant.

the condition is :

V(xi) tends to 2*xi^2 as xi tends to infinity.

I used 'dsolve' to solve the equation firstly, and got a solution with two constant C1 and C2, I want to use the condition to elimilate C2, so I used limit(sol,xi=infinity)=2*xi^2. But when I used the command 'limit', I can't get the answer.

Could any one help me? 

Many thanks!!!

I am using Maple 18 on a Mac. I also uploaded the tetrad package.  I setup my metric but when I call Christoffel I get the following error.

Download Equation_2.16_using_DiffernetialGeometry.mw

I appreciate the help.

Hi,

I'm a newer of maple .I want to prove x=z,y=z from equations of parametric z.But maple don't solve what I want,who can give me a help .thank you

howdy.

evalf(map(log10,[25,5,1,10,4,20]))=

[1.39794000867203, .698970004336017, 0., 1., .602059991327960, 1.30102999566398]

How do I reverse this process , ie get back [25,5,1,10,4,20] using map command. Obviously it's 10 to the power but map(10^,[1.39794000867203, .698970004336017, 0., 1., .602059991327960, 1.30102999566398]) won't work

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 written a program which plays the game of Multicube, a commercially made boardgame. It works OK except that when the game is replayed, the previous game output stays on the screen.  This is rather distracting and I'd like the screen cleared when a new game is run.   I'd like to know how the screen previous ouput can be cleared.   ...or what is the likely cause.

   At the start of my program I have:

restart;
interface(echo=0, verboseproc=0, warnlevel=0, prettyprint=1):

#I thought restart; would automatically have cleared any previous output.

The program reads necessary input (eg no of players, ..)  using:

x:=readline(terminal):

Thanks,  David

Hello,

I am trying to solve the boundary value problem (1-x^2)*y'' - 2*x*y' +12*y = 0 with y(-1) = -1 and y(1) = 1.  I have not used Maple much, but from some web surfing, it seems like the following inputs should work:

de := (1-x^2)*(diff(y(x), `$`(x, 2)))-2*x*(diff(y(x), x))+12*y(x) = 0

Y := dsolve(de, y(-1) = -1, y(1) = 1)

However, when I input these lines, I get the error: Error(in dsolve), found wrong extra argument(s): y(-1) = -1, y(1) = 1

Does this mean that Maple can't solve this problem?  Is my syntax wrong?  I would appreciate any help.

Thanks!

Tim

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!

Hi,

For my thesis I would like to illustrate the inclination of the solar system objects in a plane. Imagine the Solar system as a circular plane which is the average of the motions of all objects orbiting the Sun. Each individual planet/object is inclined towards this averaged plane - some more, some less. E.g. this image. Behind Neptune there lies the so-called Kuiper belt with many thousands of dwarf planets (Pluto is one of them and there are over 1000 objects known out there already). Now imagine that the big heavy Jupiter and other big planets perturb those small objects out there: so they are also inclined towards the average plane, see this image. Their inclination depends on their radial distance to the Sun (measured usually in Astronomical Units...1 unit is the distance Sun-Earth...we are talking about 40 to 50 units here). For one, I want to visualise this: imagine a circular plane and each orbit out there has another angle to the average plane. This is the first. But now: imagine the circle with it's 360°. Each object reaches it's highest point on its orbit around the Sun on another angle on this 360° circle. Neptune e.b. at 170°, Pluto at 250° etc. You get the picture. So not only are the objects in the Kuiper belt inclined differently, but their maximum orbit positions are also scattered across an imaginary 360° circle. I want to show this with a 3d-plane like this image but not with two peaks for one orbit. Is there a way to do/plot/visualise this in Maple? I am just interested in a visualisation of the principle without any empirical data behind this.

Thanks.