Hello,

I am trying to solve analytically a simple system of partial differential equations with boundary conditions and I am not able to do it. Even in the very simple case of

pdsolve([diff(u(x, y, t), y, y) = 0, diff(p(x, y, t), y) = 0, u(x, 0, t) = 1, (D[2](u))(x, 1, t) = 0, p(x, 1, t) = 2], [p(x, y, t), u(x, y, t)]);

I don't get any answer.  However if I remove the boundary conditions I get the right answer

pdsolve([diff(u(x, y, t), y, y) = 0, diff(p(x, y, t), y) = 0], [{p(x, y, t), u(x, y, t)}]);
 {p(x, y, t) = _F3(x, t), u(x, y, t) = _F1(x, t) y + _F2(x, t)}

Can maple 2015 solve analytically systems of partial differential equations with boundary conditions? I have not been able to find any example anywhere.

Thanks a lot for your help.

Javier

Hi, i'm working with some spectral acceleration data and i'm having troubles with a 'local' command on a Newmark method code i found on the internet. I'm not a maple expert so i wish someone could help me. i'm ussing maple 2015. Greetings

Newmark=proc(z0,u0,F0);  local beta,  dt, c, kg,a,b, N, i, dF, dz, du, dw, T, m, k ;        dt:=0.01;    T:=4;    N:=T/(dt);    gam:=0.5;    beta:=0.25;      m:=0.320;    k:=435;    c:=2;   z(0):=z0;   u(0):=u0;   F(0):=F0;   w(0):=(1/(m))*(F0-k*z0-c*u0);        t=vector(i,1);    t[1,1]=0;      for i from 2 to N do :  t(i,1)=t(i-1,1)+dt:  end do:           kg:=k+(gam*c)/(beta*dt)+m/(beta*dt*dt);    a:=m/(beta*dt)+(gam*c)/(beta);    b:=  (0.5*m)/(beta)+dt*((0.5*gam)/(beta)-1)*c;       for i from 2 to N do  dF(i):=diff(F,t)+a*u(i)+b*w(i);    dz(i):=(dF(i))/(kg);    du(i):=((gam*dz(i))/(beta*dt))-((gam*u(i-1))/(beta))+dt*(1-gam/(2*beta))*w(i-1);    dw(i):=((du(i))/(beta*dt*dt))-((u(i-1))/(beta*dt))-((w(i-1))/(2*beta));     z(i+1)=dz(i)+z(i);    u(i+1):=du(i)+u(i);    w(i+1):=dw(i)+w(i);     od;       plot([z(i), u(i), w(i)],x=0..50,y=-50..50);       end;

I have the following Polynomial F. Computing the genus shows that this curve has negative genus and thus is reducible. But using AFactor doesn't produce a factorization. Any ideas?

with(algcurves):
F := z^9+(-3/2+(3/2*I)*sqrt(3))*y^3*z^6+(-3/2-(3/2*I)*sqrt(3))*x^3*z^6+(-3/2-(3/2*I)*sqrt(3))*y^6*z^3+(-3/2+(3/2*I)*sqrt(3))*x^6*z^3+y^9+(-3/2-(3/2*I)*sqrt(3))*x^3*y^6+(-3/2+(3/2*I)*sqrt(3))*x^6*y^3+x^9-3*(x*y*z)^3:
z:=1:
genus(F, x, y);
evala(AFactors(F));

Hello,

I have two simple module's:

1) ------------------------------------------------------------------------

Point := proc(xx::float,yy::float)
    return module()
        local x := xx,y := yy;
        export ShowPoint,GetX,GetY;
        
        ShowPoint := proc()
            printf("Point X,Y -> [%f,%f]",x,y);
        end proc;

        GetX := proc()
            return x;
        end proc;        
        GetY := proc()
            return y;
        end proc;    
    end module:
end proc:

2) ------------------------------------------------------------------------

PointMath := module()
    option package;  
    export `+`;
    
    `+` := proc(a::Point(float,float),b::Point(float,float))
        option overload;
        Point(a:-GetX()+b:-GetX(),a:-GetY()+b:-GetY());
    end proc;
end module:

------------------------------------------------------------------------

Next I use first module:

p1:=Point(1.2,1.4);

p2:=Point(1.0,2.0);

Finally I want to add above two points:

with(PointMath)

p2:=p1+p2

The results is:

p2:=p1+p2

Why is not called operator '+' and two points are not added?

Best,

Rariusz

I want to use maple2015 to perform a Monte-Carlo simulation of a one dimensional Harmonic Oscillator.

Consider a particle having displacements, x=na where n is an integer, i.e 0 plus minus one, etc.

The potential energy of the particle is given by U(x)= 1/2 kx^2 = 1/2 ka^2 n^2.

For this simulation will choose ka^2 = 0.01 k_B T where k_B is Boltzmann's constant, and T is the temprature in Kelvin.

So we should perform a Monte-Carlo simulation starting from x(0)=20a, and perfroming individual steps by selecting an attmept to move x=+-a ,with equal probability, and choose whether to make the actual step according to energy change expected in that step.

I need to draw particle's position and x(t), and particle's energy E(t).

After that I need to calculate and draw the autocorrelation functions \phi_x(t) and \phi_E(t).

I found some code that might help me, but I am nor sure how to implement the above two lines on maple; your help is appreciated.

http://pubs.acs.org/doi/suppl/10.1021/ed100414p/suppl_file/ed100414p_si_001.pdf

Each day
a:=a+5% of a -(0.1% of a+b)-10

b:=b+5%of b -(0.1% of a+b)-10
In how many days i have a+b=0?

All the 3d plot in my maple are upside down.....the tickmarks..the numbering even the lebeling are also upside down...how do i solve it....plz help

Hello,

On a plot, how do I change the size of the probe info text box ? I cannot read the very small text displayed when the probe info is active. My laptop screen size is only 13 inches.

Thank you

I have a piecewise that exists on a large intervals, say [-5..15], however, I know need the function to represent [1..9].

There are two approaches I know of: using convert(f,pwlist) or using op(n,f), see attachments. PiecewiseTruncate.mw    and  PiecewiseTruncate.pdf

However, these two methods are not elegant enough, I have to reassemble the pieces in the new function.

How to make the solution neat?

Thanks,

I really want to use if condition inside of eval and sum, example as below:

sum(eval(y=x^(j),(if j=1 then x=2 else x=3 fi)),j=1..2)

The reason is: the value of x to be evaluated depends on the value of j which differs inside of the sum (in the context of B-spline functions).

Any lights? Thanks,

I have many integrals which I would like to calculate the value. The one in attachment is the simpliest example.

It shows 'too many level of recursion',

I know that it has something to do with the piecewise, however, it shouldn't, right? Any insights?

evalfandintPerformance.mw

evalfandintPerformance.pdf

When using maximize on a relatively complicated function (see attached Maple file and PDF), it runs extremely slow. No return after 3 minutes.

My hardward: i7 2.3G, 8G DDR3 MEM, 500G SSD.

Maybe someone is interested to try the Maple code if your workstation is more powerful? :)

MaximizePerformance.mw

MaximizePerformance.pdf

I hope to dynamically generate the function name via for loop, see enclosed Maple file and PDF file.

Any lights are appreciated.

CatOrCombineFunctionName.mw

CatOrCombineFunctionName.pdf

I am trying to do fsolve in a range (-7..14), however, it gives no solution.

But when I solve the same equations with solve (after removing all the Imaginary solutions), I get two results, one of them is in the range (-7..14). 

I even expanded the range of fsolve, say (-10..20), but still got no solution...

This is just getting weirder and weirder. Attached kindly find the Maple file, note that the first solve takes about 1 minute (on my laptop: CPU i7 + MEM 8G + SSD).

fsolve_In_Range.mw

I have a program:

Running abb(1,3) gives error: Error, (in abb) illegal use of a formal parameter

Might be a silly question: Is it not allowed? Do I have to define a local variable for b in order to change it?