Unanswered Questions

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

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

I'm trying to call a C function which returns an array. The example on the help page http://www.maplesoft.com/support/help/maple/view.aspx?path=examples/ExternalCalling is to pass in an array with known dimensions, which will be updated in the C function, but I wonder if this is the only way to do it. For example if I have an array of unknown dimensions beforehand, what is the best approach to return this array?

Thanks!


 Hello,every one,i want to solve system of equations but i recieve an error ,how can i find the coeffecients c1,c2,c3,c4?thank.

``

restart

``

``

A := 45*x*c4+72*c3 = 0:

 

B := 56*c2*c4+28*c3^2 = 0:

C := M^2*(-x^5*c4-x^4*c3-x^3*c2-x^2*c1+c1+c2+c3+c4+1)^n*c4+42*beta*c1*c4+42*beta*c2*c3 = 0:

E := M^2*(-x^5*c4-x^4*c3-x^3*c2-x^2*c1+c1+c2+c3+c4+1)^n*c3+30*beta*c1*c3+15*beta*c2 = 0:

F := M^2*(-x^5*c4-x^4*c3-x^3*c2-x^2*c1+c1+c2+c3+c4+1)^n*c2+20*beta*c1*c2-20*beta*c1*c4-20*beta*c2*c4-20*beta*c3*c4-20*beta*c4^2-20*beta*c4-20*c4 = 0:

G := M^2*(-x^5*c4-x^4*c3-x^3*c2-x^2*c1+c1+c2+c3+c4+1)^n*c1+6*beta*c1^2-12*beta*c1*c3-12*beta*c2*c3-12*beta*c3^2-12*beta*c3*c4-12*beta*c3-12*c3 = 0:

``

beta*c1+beta*c2^2+beta*c2*c3+beta*c2*c4+beta*c2+c2 = 0:

M^2*(-x^5*c4-x^4*c3-x^3*c2-x^2*c1+c1+c2+c3+c4+1)^n = 0:

with(SolveTools):

``

PolynomialSystem({{45*c4*x+72*c3 = 0}, {30*beta*c1*c3+15*beta*c2 = 0}, {42*beta*c1*c4+42*beta*c2*c3 = 0}, {20*beta*c1*c2-20*beta*c1*c4-20*beta*c2*c4-20*beta*c3*c4-20*beta*c4^2-20*beta*c4-20*c4 = 0}, {6*beta*c1^2-12*beta*c1*c3-12*beta*c2*c3-12*beta*c3^2-12*beta*c3*c4-12*beta*c3-12*c3 = 0}}, {c1, c2, c3, c4}, {beta = 2, x = 1/5})

Error, invalid input: too many and/or wrong type of arguments passed to SolveTools:-PolynomialSystem; first unused argument is {beta = 2, x = 1/5}

 

NULL

``

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Download Numerical.mw

Dear MapleSoft,

 

Would it be possible you once design a MapleSim webinar for users with more emphasis on Modelica (language, examples, etc.), on how to build more complex custom components, not just a simple DC motor? I think this would be very useful and could extend / enhance the use of MapleSime even more.

 

Tx in advance,

best regards

 

Andras

you write:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hello every one,please help me for plotting this equation(T).L=1,t=10,a=0.1,x=0..1

Table_1_for_example_1.mw

I am try to find root by using fsolve. But I am not get solution.

Please help me to solve this problem?

I have been attached the program above.

Thank You.

Best Regards.

Velmurugan G

 

 

n := 5:
z1 := exp(2*3.14*I*k1/n)*cosh(z)^(2/n);
z2 := exp(2*3.14*I*k2/n)*sinh(z)^(2/n);
xx := Re(z1);
yy := Re(z2);
uu := cos(alpha)*Im(z1) + sin(alpha)*Im(z2);

use above example of calabi yau equation, do not know which variables z, k1, k2 are u and v, then i assume k1 and k2 are u and v respectively,

 

E := diff(xx,k1).diff(xx,k1);
F := diff(xx,k1).diff(xx,k2);
G := diff(xx,k2).diff(xx,k2);

then calculate metric
diff(E, k2);
F
diff(G, k1);

which function can input these metric diff(E,k2), F, diff(G,k1) to prove calabi yau equation's metric's ricci is flat

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