Melvin Brown

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I am unable to replicate solution of problem 169 below.  Can you help me debug?

Melvin Brown

Schrdiff(o(t), t, t)dinger PDE on (x,y,t) with initial and boundary conditions. Zero potential: problem number 169


Here is the problem 169 specification and solution from the Nasser list:


with(PDEtools); with(CodeTools)














I*(diff(f(x, y, t), t)) = -(1/2)*hbar^2*(diff(diff(f(x, y, t), x), x)+diff(diff(f(x, y, t), y), y))/m



f(x, y, 0) = 2^(1/2)*(sin(2*Pi*x)*sin(Pi*y)+sin(Pi*x)*sin(2*Pi*y))



f(0, y, t) = 0, f(1, y, t) = 0, f(x, 1, t) = 0, f(x, 0, t) = 0


cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve([pde,ic,bc],f(x,y,t))),output='realtime'));

memory used=159.58MiB, alloc change=102.00MiB, cpu time=4.37s, real time=4.23s, gc time=452.40ms




with(plots); evalf(f(1, 2, 2))

f(1, 2, 2)


plot3d(f(x, y, 3), x = -1 .. 1, y = -1 .. 1)

Warning, expecting only range variables [x, y] in expression f(x,y,3) to be plotted but found name f



The problem seems to fail... Why?




I get the following when MAPLE starts...

Warning, .hdb help databases are deprecated, 'C:\Program Files\Maple 2018\lib\OrthogonalExpansions.hdb' will not be used, see ?HelpTools,Migrate help page for more information

I have recently loaded an orthogonal expansions package created for earlier versions of MAPLE.

How can I remove the message?


Does MAPLE have capabability to do multidimensional FTs i.e. (x,y)->(u,v)? If not, are there any links to MAPLE packages which meet this requirement that can be recommended?

Melvin Brown



Dear Support

I am attempting to model quantum dynamics, and have defined a coupled set of nonlinear PDEs I would like to solve for coupled solutions u(x,y,t) and v(x,y,t) using MAPLE 18.

I attach an image of part of the worksheet the pair of PDEs...The initial conditions u(x,y,0), v(x,y,0) are a pair of respectively positive and negative 2D gaussians on the x,y, domain.

Before I go any further, please would you check that MAPLE 18 is in principle capable of finding solutions u(x,y,t), v(x,y,t) solutions, and let me know whether it is worth pursuing the solution?  I have had a look at the MAPLE documentation, but am not sure whether MAPLE can solve this system.

As a warm-up, I successfully solved a 1-D system u(x,t), v(x,t) using pdsolve[numeric], but I am not clear whether MAPLE 18 can solve for u(x,y,t), v(x,y,t) either numerically or analytically on the [x,y,t] domain.

I hope you can provide help/guidance. An image the equations in MAPLE is displayed here...

Melvin Brown


I understand that Maple 2018 is now able to solve 3 independent variable PDE & BC problems in bounded domains through separation of variables by product and eigenfunction expansion.

My solution domain is (x,y,t), (i.e three independent variables) but I would like to need to use numerical integration.  Are there plans to make numerical integration for PDEs with three independent availables, and if so when is that facility likely to be available?




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