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Dear all

I have query related to generating commutator table from given Lie algebra spanning symmetries of PDE, I have ten vectors that I need to commute with each other to constitute commutator table. I have calculated all the commutations manually using "symmetrycommutator" command.

My queries is, can I convert this operation into short loop type program which automatically calculate cummutation of vectors from 1 to 10.

The Maple file is attaches with this query for reference.

Hello All,


I am doing research for my master's thesis and I am trying to type a PDE into maple and have been struggling for about 2 weeks now. I am new to Maple but have had a lot of Matlab experience. I've seen a couple of ways to do variable changes and things but I'm still.


These are the substitutions I'm trying to do.

into this equation, but and some of these terms are 0 (x*d/dt are 0, P, and M_e, and q_ye).

 So it is basically a Euler-Bernoulli beam with a free vibration.

I tried to use dchange to do the substitutions but I am having trouble defining ...

 or doing both



 I see why there is an error but I don't know how to fix it.


I've also tried

Which is close but still doesn't look quite right. because d/dt(omega*t/2) -> omega/2


Any thoughts?


Thanks in advance

How using Maple one can obtain commutator and adjoint table for given set of infinitesimal generators spanning Lie symmetries for PDE?

pde1 := 4*x*(diff(u(x, y), x))-2.*u(x, y)-y*(diff(u(x, y), y))+diff(v(x, y), y) = 0; pde2 := 4.*x.u(x, y).(diff(u(x, y), x))+(v(x, y)-y.u(x, y)).(diff(u(x, y), y))+2.*u(x, y)^2 = diff(u(x, y), `$`(y, 2))+theta(x, y); pde3 := 8.*u(x, y).theta(x, y)+4.*x.u(x, y).(diff(theta(x, y), x))+(v(x, y)+y.u(x, y)).(diff(theta(x, y), y)) = 1/100.(diff(theta(x, y), `$`(y, 2))); bc1 := u(x, 0) = 0, v(x, 0) = 0, theta(x, 0) = 1; bc2 := u(0, y) = 0, v(0, y) = 0, theta(0, y) = 0; bc3 := u(x, 20) = 0, theta(x, 20) = 0hello dear
how can i solve this three couplde pde?please help me


with(DETools, diff_table);

kB := 0.138064852e-22;

R := 287.058;

T := 293;

p := 101325;

rho := 0.1e-2*p/(R*T);

vr := diff_table(v_r(r, z));

vz := diff_table(v_z(r, z));

eq_r := 0 = 0;

eq_p := (vr[z]-vz[r])*vr[] = (vr[]*(vr[r, z]-vz[r, r])+vz[]*(vr[z, z]-vz[z, r]))*r;

eq_z := 0 = 0;

eq_m := r*vr[r]+r*vz[z]+vr[] = 0;

pde := {eq_m, eq_p};

IBC := {v_r(1, z) = 0, v_r(r, 0) = 0, v_z(1, z) = 0, v_z(r, 0) = r^2-1};

sol := pdsolve(pde, IBC, numeric, time = z, range = 0 .. 1);


what am I doing wrong?

it's telling me: Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 3, got 2
but i did just as in the example :-/

Are there any commands in maple that will help me find a suitable function that approximates the numerical solution of:

  PDE := diff(v(x, t), t) = diff(v(x, t), x, x);
  JACOBIINTEGRAL := int(JacobiTheta3(0, exp(-Pi^2*s))*v(1, t-s)^4, s = 0 .. t);
  IBC:= D[1](v)(0,t)=0,
        D[1](v)(1,t)=-0.000065*v(1, t)^4,
# For x=0..1, t=0..1, the solution varies only very slowly
# so I have increased the timestep/spacestep, just to speed
# up results generation for diagnostic purposes
  pds := pdsolve( PDE, [IBC], numeric, time = t, range = 0 .. 1,
                  spacestep = 0.1e-1, timestep = 0.1e-1,

diff(v(x, t), t) = diff(diff(v(x, t), x), x)


int(JacobiTheta3(0, exp(-Pi^2*s))*v(1, t-s)^4, s = 0 .. t)


(D[1](v))(0, t) = 0, (D[1](v))(1, t) = -0.65e-4*v(1, t)^4, v(x, 0) = 1




# Plot the solution over the ranges x=0..1,
# time=0..1. Not a lot happens!
  pds:-plot(x=1, t=0..1);


# Plot the estimated error over the ranges x=0..1,
# time=0..1
  pds:-plot( err(v(x,t)), x=1,t=0..1);


# Get some numerical solution values
  pVal:=pds:-value(v(x,t), output=procedurelist):
  for k from 0 by 0.1 to 1 do
      pVal(1, k)[2], pVal(1, k)[3];


t = 0., v(x, t) = Float(undefined)


t = .1, v(x, t) = .999977377613528229


t = .2, v(x, t) = .999967577518313666


t = .3, v(x, t) = .999959874331053822


t = .4, v(x, t) = .999952927885405241


t = .5, v(x, t) = .999946262964885979


t = .6, v(x, t) = .999939702966688881


t = .7, v(x, t) = .999933182128311282


t = .8, v(x, t) = .999926675964661227


t = .9, v(x, t) = .999920175361791563


t = 1.0, v(x, t) = .999913676928735229





Download PDEprob2_(2).mw


I am refering to the first graph, is there a way in maple to find an explicit suitable approximating function?

I.e, I want the function to have the same first graph obviously, it seems like addition of exponent and a line function, I tried plotting exp(-t)-0.3*t, it doesn't look like it approximates it very well. Any suggestion on how to implement this task in maple?



Hello everyone.

Tell me how to solve this equation grad(div(f(x,y,z)))+K*Laplacian(f(x,y,z))=0

Here, the function f defines a vector field.

I tried so



Physics:-Vectors:-Setup(mathematicalnotation = true)

[mathematicalnotation = true]


eq := Gradient(Divergence(f(x, y, z)))+K*Laplacian(f(x, y, z)) = 0

Error, (in Physics:-Vectors:-Nabla) Physics:-Vectors:-Divergence expected a vector function, but received the scalar function: f(x, y, z)





Are there any examples of network solutions such as mine systems in Maple.
I wrote in the Maple system of partial differential equations describing the process of filtration combustion.
I'm a novice. I do not quite understand how to solve it.
Online a lot of "simple" examples. I need something very similar to my case.

I am trying to solve system of partial differential equation, but i got some trouble. This is system of heat equations

Here are the equations:

U1 := diff_table(u1(x,t)):
pde[1] := (1/kappa1)*U1[t]=U1[x,x];

bc[1]:=u1(-L, t)=V;


U2 := diff_table(u2(x,t)):
pde[2] := (1/kappa2)*U2[t]=U2[x,x];

bc[2]:=u2(a, t)=0;


sys:=[pde[1],bc[1],pde[2],bc[2], u1(x=0,t)=u2(x=0,t), 





a and L is arbitrary constanta

anyone can help? The last boundary conditions I mean du1/dx=du2/dx at x=0

How can i solve this problem? 

I have the solution to a heat PDE, v and the error esitmate u + cos(x+t) = v


I want to plot log v(1,t) as function of log u(1,t) in maple, but I seem to get an error:

Error, (in plot) unexpected option: ln(u(1, t))


I am attaching my code below.

How to fix this problem?

Thanks in advance.


     I'm trying to solve this PDE, and Maple 2015 gives me a solution quickly. I can test the solution with pdetest() and this verifies that it works. However, when I try to verify this myself I don't get zero. Is there some trick pdetest() is using to that I am missing? Or is pdetest() wrong in this case?



eq := I*exp(-(2*I)*k*t)*k*sin(theta)*r^2*cos(theta)^3+4*exp(-(2*I)*k*t)*r*cos(theta)^3+2*(diff(Vr(t, r, theta), theta, theta))*cos(theta)*exp(-I*k*(sin(theta)*r+t))-6*(diff(Vr(t, r, theta), theta))*sin(theta)*exp(-I*k*(sin(theta)*r+t))-4*Vr(t, r, theta)*cos(theta)*exp(-I*k*(sin(theta)*r+t))-4*exp(-(2*I)*k*t)*r*cos(theta);

I*exp(-(2*I)*k*t)*k*sin(theta)*r^2*cos(theta)^3+4*exp(-(2*I)*k*t)*r*cos(theta)^3+2*(diff(diff(Vr(t, r, theta), theta), theta))*cos(theta)*exp(-I*k*(sin(theta)*r+t))-6*(diff(Vr(t, r, theta), theta))*sin(theta)*exp(-I*k*(sin(theta)*r+t))-4*Vr(t, r, theta)*cos(theta)*exp(-I*k*(sin(theta)*r+t))-4*exp(-(2*I)*k*t)*r*cos(theta)


sol := pdsolve(eq);

Vt(t, r, theta) = _F2(t, r)/cos(theta)^2+sin(theta)*_F1(t, r)/cos(theta)^2-((1/2)*I)*(cos(theta)^2*k^2*r^2-2)*exp(I*(sin(theta)*r-t)*k)/(k^3*r^2*cos(theta)^2)


pdetest(sol, eq);



eq2 := eval(eq, Vr(t,r,theta) = rhs(sol)):
eq2 := simplify(%);

-((1/2)*I)*exp(-(2*I)*k*t)*k*r^2*cos(theta)^3+2*exp(-(2*I)*k*t)*r*sin(theta)*cos(theta)-3*(diff(Vt(t, r, theta), theta))*sin(theta)*exp(-I*k*(sin(theta)*r+t))-2*Vt(t, r, theta)*cos(theta)*exp(-I*k*(sin(theta)*r+t))+(diff(diff(Vt(t, r, theta), theta), theta))*cos(theta)*exp(-I*k*(sin(theta)*r+t))


evalb(eq2 = 0);







Hi everyone.

I'm trying to solve the following PDE


but I'm getting this error:

Error, (in pdsolve/numeric/process_IBCs) initial/boundary conditions can only contain derivatives which are normal to the boundary, got (D[1, 1](w))(x, 0)

The PDE represents the bending of a thin plate.

See File:

I am getting the following expression when I partially differentiate an expression:

PDE11 := diff(theta(z, p), z, z, p)+2*lambda(p)*theta(z, p)*(diff(lambda(p), p))+lambda(p)^2*(diff(theta(z, p), p))+lambda(p)^2*(sin(theta(z, p))-theta(z, p))+2*p*lambda(p)*(sin(theta(z, p))-theta(z, p))*(diff(lambda(p), p))+p*lambda(p)^2*(cos(theta(z, p))*(diff(theta(z, p), p))-(diff(theta(z, p), p)))

I differentiate the above equation to get each term in the form of :table([f=......])

(table([f = 1+sum(Lambda[n](0)/factorial(n), n = 1 .. infinity)]))(p)^2

It is difficult to understand the expression. Maple does not show any error. Can you please tell me what the error is?

Hi !

I am trying to solve a pde with initial/boundary conditions, in the numeric mode. It works very well when I provide 3 numerical conditions : 1 initial condition (uniform distribution at first), and two boundary conditions.

Now I want to switch the initial condition to a function of r. It's a polynome I obtained after interpolation of another result. I tested it and the function interp20(r) works. But the pdsolve doesn't seem to evaluate the function, when it comes to start the procedure and pdsolve doesn't return a module as it should, although it doesn't send any message error.

You can see the code following, with the error messages I get.


Is it strictly impossible to use a function as an initial condition ?
Is it just a problem I could solve by converting the function or its result to something else ?
Is float the right type of input ? For example, if I write a:=283.15, is it a float ?
Have you already had similar problems ? How did you solve them ? Where could I find working code examples on this ?
Could I solve this problem with non-uniform initial condition with another Maple function ?

Then you very much for your help !



I am trying to solve a PDE which is converted to ODE when we assign one of the  variables some value. The boundary conditions given to the PDE are numerical values given for fixed numerical values to the two independent variables. I am trying to solve the PDE with the staandard syntax:

pds := pdsolve(pde,[ibc],numeric,time=z,range=0..beta);

The error message I get is:  

Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {theta(z, 0)}

The pde and boundary conditions are as follows:

PDE:   pde := diff(theta(z, 0), z, z)+theta(z, 0)

Where zero is the fixed value for an independent variable

Boundary Condition:  ibc:={theta(0,0)=beta,D[1](theta)(0,0)=0};

When I try to solve it as an ODE the error is:

Error, (in dsolve) not an ODE system, please try pdsolve


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