Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

 

# I solved the differential equation using a fourier series decomposting method. I found with the help of "Dsolve" the different expressions of the fourier constants and now I will apply the boundary conditions to find the expressions of its constants.

#this my boundary conditions

#this my system of equations

Can a second plot be added to a plot generated by a plots[odeplot] command for the case below?

> dsn := dsolve(eval(ddesys, {beta = 4, gamma = 0.0478, sigma = 0.10,tau__1 = 1.1,tau__2 = 8.7}), numeric):

> plots[odeplot](dsn, [[t, S(t), color = green], [t, Ex(t), color = black], [t, Ix(t), color = blue],[t, R(t), color = red]],  0 .. 100, legend = [ S(t), Ex(t), Ix(t), R(t)], labels = [t,""] );
 

Why does Maple product history page   stop at Maple 6, year 2000?

Maple starterd in 1984. There are more versions before version 6. I think this official Maple page should list every release made in Maple and do not understand why it stop at version 6 only.

Wikipedia has more complete and detailed history of Maple products, starting with version 1 in 1982, with minor versions also shown than Maple own official web page gives.

btw, Wilipedia says version 6 was released in December 6, 1999. But Maple official page says version 6 was released in 2000.  

 

Hi,

I'm trying to change with a Maple Worksheet the parameters of a MapleSim Model in Real-matrices format.

is there any way to do that?

actually i get the failure note:

<<Error, (in SetParameters) non-vectorized values in vector parameters: [list= ""]>>



 

Thank You

Regards
Johann
 

How to futher simplify so that we could exact value

Hello

I use Maple 20018.2.

When I use "Data Set Search" and press Search I get following Error Message. I check that the network access to the internet is on enable. Does anybody has an Idea?

thank you

Murad

I'm trying to obtain the dynamical response of a simply-supported beam with a cantilever extension, coupled to a spring-mass system. In mathematical terms, this system is ruled by three PDEs (relative to each bare part of the main structure) and one ODE (relative to the spring-mass system). I think my mathemical model is finely formulated, but Maple keeps telling me this:

Error, (in pdsolve/numeric/process_IBCs) improper op or subscript selector

I believe it is because my PDEs depend on "x" and "t", while the ODE depends solely on "t". I have tried to transform my ODE into a "PDE", making it also dependent of "x", but without imposing any boundary conditions relative to "x". However, after this Maple points a new error message:

Error, (in pdsolve/numeric) initial/boundary conditions must be defined at one or two points for each independent variable

Could someone help me finding a solution? My algorythm in shown in the attached file below.

Worksheet.mw

Hello

I wonder if someone on the list can give me some guidelines on how to use Grid:-Seq.

I have applied Grid:-Set and Grid:-Seq to one of my problems where parallelization is a possibility.   In this problem, I have a massive list of lists that needs to be processed in chunks and then a new list is returned.

What I've found so far:

1) Grid-Seq won't work if I use a procedure from a private module that calls local (or exported) functions of the same module.  Solution:  I need to use savelib (there is a bug in Grid:-Seq)

2) Grid-Seqs seems to be working fine up to a point where it simply stops.  For example:   Starting with 431895 sets, the procedure divides them into 864 sets of 500 elements (the last one does not usually contain 500 elements).  Then I use res:=Grid:-Seq['tasksize'=9](myFunction(newSets[i],...,....),i=1..864).   The messages sent out by Grid:-Seq are 

Seq: using tasksize=9; number of elements= 864, number of partitions = 96

......

Seq: done sending all partitions

Seq: received results from all nodes; collating results

After two hours running and using 36 cores, the result is available in res.  The next step is to use the results in res for another cycle of calculations.  1503462 sets = 3007 sets of 500 elements.  The messages sent out by Grid:Seq are 

Seq: using tasksize=9; number of elements= 3007, number of partitions = 335

......

Seq: done sending all partitions

The last message showed up on the screen after an hour. During the process, I saw the current tasks finishing and new ones starting.  However I could not see "Seq: received results from all nodes; collating result" after a day running.  I am using timelimit to be sure that all calculations will finish no matter what.  

I have checked the system information and found that: 1) all 72 cores are running but they are jumping from 0% to 100% (in the example that works I could see all of them in 100% solid), 2) Memory is at 156 GB (200 Gb is the limit) and no swap to disk.

I have also noticed:

  1. If I use Maple 2017, not even the first example works.
  2. tasksize=9 somehow helps with similar problems.  If the size is left for Maple to decide, it seems that the problem happens for sets of smaller size.
  3. On linux I had to use "kill -9" to remove maple from every single core. My impression is that Grid:-Seq does not clean up the processes after they finished.  
  4.  The problem seems to be on "results from all nodes; collating result".

 

I know that the explanation above in rather vague, but if someone has any clue or guidelines on how to solve this problem, please share it with me.

 

Many thanks

 

Ed

 

 

 

Hello everyone, 

I have a parametric plot which you can see in the first image below, g and t are both functions of (p,v). I have fixed the value of p in the functions then plotted for v, and you can see the resulting plot (i am only interested in the blue figure) there is an intersection. 

The maximum value p is aloud to have in my functions 1/(12*pi) which i am approximating to 0.026. So what i am trying to do is for p from 0.026 to 0 obtain values of t for each p then plot then with pointplot with arrays i have made after solving the equations. However the plot which i am obtaining is not matching what i want see second image below. 

 

I have attached my code so you can see what i have done and how my image doesnt match any help would be appreciate, Thanks.Solving_Equation_.mw

restart;
plot([sin(x), sin(x), x=0..420]);

The matrix A := op([1,1], %)  has equal columns, so the bug is in the PLOT engine.
plot(A) generates the same plot.
See also the "circle":
plot([cos(x), sin(x), x=0..5000*Pi]);

 

Dear all

I need to display a matrix K defined in the attached maple code.

Thanks for your help

matrix.mw

If A then B After clustering B , how to find a set of A in machine learning topic and fuzzy topic?

Hi, 

I represent 3 thin parallel slices of colors red, green and blue; all have the same transparency equal to 0.5
For the default orientation of the display, the blue slice is on the forefront, the red one in the background and the green one in beween. Then the blue slice is "bluer" than green and  the green one "greener" than red (FIG 1)
If you rotate manually the figure in order to place the red slice in the forefront and the blue one in the background, you expect to have the red slice "redder" than the green one and the green one "greener" than the blue one (FIG 2)
This is not the case.

The order in which the slices appear in the PLOT3D command defines the foreground and the background, but these latter are not dynamically recalculated when the figure is rotated.
To recover the correct colors one must revert the order of the slices in PLOT3D (FIG 3)

Are we comdamned to change to change manually the order of the slices in PLOT3D or does it exist an option whixh avoids doing so?

Don't pay too much attention to the plots above for the foreground is strangely correct on figure 2 ???

restart

with(plottools):

alpha := Pi/18.:
a := 2*cos(alpha):
b := 2*sin(alpha):
e := 0.02:
p := [[0,0,0],[a,b,0],[a,b,1],[0,0,1]],
     [[0,e,0],[a,b+e,0],[a,b+e,1],[0,e,1]],
     [[0,0,0],[0,e,0],[0,e,1],[0,0,1]],
     [[a,b,0],[a,b+e,0],[a,b+e,1],[a,b,1]],
     [[0,0,0],[a,b,0],[a,b+e,0],[0,e,0]],
     [[0,0,1],[a,b,1],[a,b+e,1],[0,e,1]]

[[0, 0, 0], [1.969615506, .3472963554, 0], [1.969615506, .3472963554, 1], [0, 0, 1]], [[0, 0.2e-1, 0], [1.969615506, .3672963554, 0], [1.969615506, .3672963554, 1], [0, 0.2e-1, 1]], [[0, 0, 0], [0, 0.2e-1, 0], [0, 0.2e-1, 1], [0, 0, 1]], [[1.969615506, .3472963554, 0], [1.969615506, .3672963554, 0], [1.969615506, .3672963554, 1], [1.969615506, .3472963554, 1]], [[0, 0, 0], [1.969615506, .3472963554, 0], [1.969615506, .3672963554, 0], [0, 0.2e-1, 0]], [[0, 0, 1], [1.969615506, .3472963554, 1], [1.969615506, .3672963554, 1], [0, 0.2e-1, 1]]

(1)

f   := k -> transform((x, y, z) -> [x, y+k, z]):
col := k-> COLOR(RGB, op(ListTools:-Rotate([1, 0, 0], -k))):
t   := TRANSPARENCY(0.5):
PLOT3D(POLYGONS(p, t, col(0)), f(1)(POLYGONS(p, t, col(1))), f(2)(POLYGONS(p, t, col(2))), AXESLABELS(2, 3, 1))

 

PLOT3D(POLYGONS(p, t, col(0)), f(1)(POLYGONS(p, t, col(1))), f(2)(POLYGONS(p, t, col(2))), AXESLABELS(2, 3, 1))

 

PLOT3D(f(2)(POLYGONS(p, t, col(2))), f(1)(POLYGONS(p, t, col(1))), POLYGONS(p, t, col(0)), AXESLABELS(2, 3, 1))

 

 


 

Download Background_Foreground.mw

Coming across this post upon investigating relational symbols available in Maple that I am yet to use, (the first listing in the search results):

https://math.stackexchange.com/questions/1929439/what-does-square-subset-and-square-union-symbol-mean

I again wish to reinforce the motive behind a post I previously made, and that is that a stack exchange maple community would be beneficial to education in general.

I also want to point out that I have no stake in this, I am an average user of both the Stack exchange mathematics domain, and an average user of Maple, neither of which I am employed by or would be in any realistic forseeable future.

 

Not that I care about the virtual rating numbers here, but I am wondering why would one suddenly lose 15 point after posting a problem they found in Maple? Is this typical?

https://www.mapleprimes.com/questions/229443-Why-These-ODEs-Hang-Or-Return-Unsolved

3 hrs ago, I was 3001  and when I came to check on the status if any, now it says 2986.

Just wondering why, that is all. Again, this really does not bother me at all as I do not care about these virtual cloud credit points, and I only post here on occasions and when I found some problem. I just like to know why this happened just now, that is all. 

 

 

 

 

 

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