Unanswered Questions

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

let aa = map (+1.2) [1,2]
let bb = map (+1.4) [2,3]
foldr (aa . bb) [3.0,4.0]

I tried to use a for loop to assign the bounds for creating an RTable in a Maple C wrapper (actually it does not matter what I do here). I checked that the for loop syntax is correct C syntax, for example even as simple as for (int i = 0; i < 2; i++){...} but the loop becomes an infinite loop and takes forever to run. Has anyone encountered the same problem as I did

 Hi everybody,

Until recently I was using Maple 2015.0 on this PC :

Windows XP
2 dual core proc Intel(R) Xeon(R) CPU E3-1225 V2 ; 3.19 GHz
64 bytes,
16 Go RAM

For two days now I am using Maple 2015.0 on this one

Windows 7
4 dual core proc Intel(R) Xeon(R) CPU 5-2637 V3 ; 3.50 GHz
64 bytes,
64 Go RAM


Comparisons of the running times for exactly the same code, consisting in 10000 independent Monte Carlo  simulations distributed over all the nodes (resp 4 and 8) give :

Windows XP :  504 sec  (with a variation of the order of  +/- 3s for different replicates)

Windows 7   :  343 sec  (with a variation of the order of  +/- 3s for different replicates)


The expected running time should be 504 * (3.2/3.5) * (4/8) = 230 s
(or 504 * (4/8) = 252 s if you neglect the acceleration due to the clock rate)
The realized running time (343 s) is thus at least  40% larger than the expected one.


Does anybody has already observed this kind of performance loss during XP -> 7 migration ?
Are there some comparisons of cpu times between Windows XP and 7 ?


Thank you all for sharing your own experience.



postscript : a NOTIONALexample of how the computations are distributed is given below

NbOfRuns := 10000:

# Data is a Matix(NbOfRuns, NbOfCols, …) constructed elsewhere

NbOfNodes := Grid:-NumNodes():
NbOfRunsPerNode := NbOfRuns / NbOfNodes:
for k from 0 to NbOfNodes do
   FirstData := 1 + k * NbOfRunsPerNode:
   LastData := (k+1) * NbOfRunsPerNode:
   Grid:-Run(k+1, MyCode, [Data[FirstData..LastData, ..], …])
end do:

I'm trying to view the source of the webpage fuelsonline.ca

I used HTTP[Get] like I did before which doesn't retrieve much of anything useful.  I thought of the sockets package which I can't seem to pull any information from.  Then I had an idea and viewed the page source which finally has information I can use if I can get Maple to read it in.  If I can get Maple to pull in the contents of the page source I should at least be able to carry it from there. 

Any ideas from anyone?

Hello, I run Maple to solve Binary Integer Programming problem which contain about 1340 constraint and its goal to maximize the objective function.

At first, it's running for 2 hours and said that the iteration limit was reached. So I try to add 'iterationlimit' at LPSolve opts and set it to 10000, but after 3 or 4 hours it said that the iteration limit was reached. So I set 'iterationlimit' to 100000000 and now Maple keep evaluating more than 12 hours.

I run Maple at my notebook with these spesification:

Processor: Intel Corei3-5005U 2.0 GHz

Memory: 4GB RAM

Windows 10

 

It is normal? Or I must run Maple in higher notebook spesification?

Thank you in advance.

 

Below is my Maple file, hope you can help me.

ISL_2017_FASE3.mw

I have created a model for a robot in Solidworks and have imported it into Maplesim using the CAD toolbox. The problem I have is that the robot has 3 arms that are supposed to come together on a central piece pictured below in figure 1, but attempting to simulate the model with all arms connected with a revolute joint as in figure 2 yields an error that says "The system is underdetermined" the location of the error is main.

For the purposes of the image below I only connected one of the arms, this allows Maplesim to run the file successfully.

figure 1 showing the central piece that the 3 arms are supposed to connect to.

 

Figure 2 showing the problem revolute joints circled in black, the error at the bottom and the setting of the revolute joint on the right.

 

Essentially my question is how do I get the model to work? I apologise if this problem is not terribly well demonstrated, this is my first post onto this forum so I am not sure of all the standards.

I am a beginner with Maplesoft.

I have a data file with several devices IDs and links between these devices (more than 5000 links). For representing a network in Maple, I am aware that the GraphTheory package should be used. The vertices and edges are to be defined and the graph to be displayed.

The examples that I have looked at do not have such a large number of links. With more than 5000 links in the data file, I am not sure how to proceed further.

Any help or pointers would be highly appreciated.

Hello all,

I've been writing this procedure and it all works apart from the final sequence. I don't know why the final sequence doesn't input a number. Any suggestions? Thank you in advance!

Gambia ManTest_2.mw

In my study, I often need to verify that two operator is symmetric i.e. [P,Q]=PQ-QP=0, where A and D are operator polynomial such like  D2+4u+uxD-1 multiply with D3+uD+ux,where D is differential operator.

I tried to use the Ore_package which can easily deal with the operator polynomial without integral(i.e. D-1 term), so in my case , how to deal with operator with both differential and integral?

Wondering if anyone has created a Maple "front end" for handling SLAB calls.

 

 

Hello guys, i would like to do parallel computation in my code written in the Maple18. The question that can help me is:

Given a procedure that compute an function g, where g = f1+f2+f3+f4+f5+f6+f7+f8, i would like to compute all fi at same time.
Now, i´m using " grid:-seq('f[i]',[i=1,2,3,4,5,6,7,8])" and it works very well. However, i think that for my case an better solution should be;
Calculate the f1 in core 1, f2 in core 2, f3 in core 3 ... f8 in core 8 at same time, and after this, to sum all results(f1+f2+f3+..+f8). How i can do this?

Att,

Griffith.

import com.maplesoft.openmaple.*;

import com.maplesoft.externalcall.MapleException;

class test

{

    public static void main( String args[] )

    {

        String a[];

        Engine t;

        int i;

        a = new String[1];

        a[0] = "java";

        try

        {

            t = new Engine( a, new EngineCallBacksDefault(), null, null );

            t.evaluate( "int( x,x );" );

        }

        catch ( MapleException e )

        {

            System.out.println( "An exception occurred\n" );

            return;

        }

        System.out.println( "Done\n" );

    }

}

This code error import com.maplesoft.externalcall.MapleException in java?

Please help me.

http://www.maplesoft.com/support/help/Maple/view.aspx?path=OpenMaple/Java/Examples

I was trying to call a C shared library which calls a Python function. I got the following error:

Error, external linking: error loading external library

/directory/of/my/library/libbe.so: libpython2.7.so.1.0: cannot open shared object

file: No such file or directory

 

Since I was running this using a pbs file, I made sure that I exported LD_LIBRARY_PATH (to libpython.so) inside the specific node. Does anyone have ideas on why this happens? Thank you!

Hey there,

I am using the fsolve command in order to solve numerically a system of equations with N equations and N unknowns. According to my discretization the number of equations changes. If I have a small number of equations it all works out perfectly. But if I increase the number of equations I just get something like that:

Sorry, for the long post, but for a small number of unknowns Ai it works. It seems that maple doesnt try to compute? Has anyone encountered the same problems?

 

Any help is appreciated.

Jens

Dear All

It is well known that the package "PDEtools" is helpful in finding infinitesimal transformations for PDEs which I illustrate as follow:


with(PDEtools):

DepVars := [u(x, y, t)]

[u(x, y, t)]

(1)

declare(u(x, y, t)):

u(x, y, t)*`will now be displayed as`*u

(2)

U := diff_table(u(x, y, t)):

PDE1 := U[t, x]+(3/2)*u(x, y, t)*U[x, x]+(3/2)*U[x]^2+(1/4)*U[x, x, x, x]+(3/4)*sigma*U[y, y] = 0:

G := [seq(xi[j](x, y, t, u), j = [x, y, t]), seq(eta[j](x, y, t, u), j = [u])]:

declare(G):

eta(x, y, t, u)*`will now be displayed as`*eta

 

xi(x, y, t, u)*`will now be displayed as`*xi

(3)

DetSys := DeterminingPDE(PDE1, G, integrabilityconditions = false):

pdsolve(DetSys)

{eta[u](x, y, t, u) = (1/9)*(-2*(diff(diff(diff(_F1(t), t), t), t))*y^2-4*(diff(diff(_F2(t), t), t))*y+6*sigma*(-(3/2)*(diff(_F1(t), t))*u+(1/2)*(diff(diff(_F1(t), t), t))*x+diff(_F3(t), t)))/sigma, xi[t](x, y, t, u) = (3/2)*_F1(t)+_C1, xi[x](x, y, t, u) = (1/6)*(-2*(diff(diff(_F1(t), t), t))*y^2-4*(diff(_F2(t), t))*y+3*sigma*((diff(_F1(t), t))*x+2*_F3(t)))/sigma, xi[y](x, y, t, u) = (diff(_F1(t), t))*y+_F2(t)}

(4)

The set (4) gives infinitesimal transformations. How we can write  vector fields corresponding to arbitrary constant C1and arbitrary functions "F1(t), F2(t), F3(t) "?"" 

``


Download Writing_Vector_fields.mw

Regards

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