I am attempting to use the pdsolve function in Maple to explicitly solve a PDE which is basically a perturbation of the Laplace equation.  Nothing happens when I enter pdsolve, however, is this because a boundary condition is also needed to produce a solution?  The BC which I have is that f(x, y, z) goes to zero as sqrt(x^2 + y^2 + z^2) goes to infinity but I am not sure how to enter such a BC in Maple.

PDE := diff(diff(f(x, y, z), x), x) + diff(diff(f(x, y, z), y), y) + diff(diff(f(x, y, z), z), z) - exp(-t*exp(sqrt(x^2 + y^2 + z^2)))*(diff(diff(f(x, y, z), x), x) + diff(diff(f(x, y, z), y), y) + diff(diff(f(x, y, z), z), z))/(1 + m/(2*sqrt(x^2 + y^2 + z^2)))^4 = 3/2*exp(sqrt(x^2 + y^2 + z^2) - t*exp(sqrt(x^2 + y^2 + z^2)))*(diff(f(x, y, z), x)*tx/sqrt(x^2 + y^2 + z^2) + diff(f(x, y, z), y)*ty/sqrt(x^2 + y^2 + z^2) + diff(f(x, y, z), z)*tz/sqrt(x^2 + y^2 + z^2))/(1 + m/(2*sqrt(x^2 + y^2 + z^2)))^4;

pdsolve(PDE);

Hello, 

I am doing symbolic calculations of multi-body kinematics which involves more than 40-degrees of freedom. I built a module that will construct initial kinematic calculations and it finshes fairly quicly, (about 20s). When I want to retrieve these calculations, stored as proprties of the module, it takes really a long time, we are talking more than 30min. It's strange because these calcualtions were already made during the initalization of the module, I am just retriving them for the purpose of writing the symbolic results to a file to later be used in Matlab as functions. 

Any word of advice?

Thanks. 

I was computing an integral (Running Maple 18 on Windows 10):

The classic lenght of arc Integral of sqrt(1+(dy/dx)^2) dx

In this case, the function was a cartesian circle (x-R)^2+y^2=R^2 isolated as y=sqrt(R^2-(x-R)^2)

When I do the integration, the result of the integral is not correct.
But if I change R for a, the result is correct. Why? This does not make any sense.

R wasn't assigned to any variable. The code was:

Good Integral

[>y:=expand(sqrt(a^2-(x-a)^2));
[>f:=expand(simplify(sqrt(1+diff(y,x)^2)));
[>S:=int(f,x)+K;

Wrong Integral

[>y:=expand(sqrt(R^2-(x-R)^2));
[>f:=expand(simplify(sqrt(1+diff(y,x)^2)));
[>S:=int(f,x)+K;

In fact, any UPPERCASE letter used as the radius gives me the wrong answer whereas any LOWERCASE letter gives me the proper result. Why is this?

Thanks and have a nice day
EDIT: I added a Screenshot

Hi

My integrals are convolutions.and I know I can evaluate this using numerical integration, but I am seeking a numerical solution of this problem using FFT. I have many many integrals of this type to evaluate and I need FFT for speed reasons.

fft.mw

This might inspire you.

https://www.mathworks.com/matlabcentral/answers/228107-how-to-evaluate-a-convolution-integral-by-fast-fourier-transform

Hello, 

I build a small simple custom library in MapleSim, for some reaon MapleSim is keep giving me that a variable can't be resolved and that there is no "LibraryName" visible. 

The library loads successfully with no error though. 

exact msg:

Cannot resolve type `MyLibrary.Dh_Revolute` of variable `Main.DR1` in model `Main`; there is no `MyLibrary` visible

thanksf or your help. 

I bought a subscription for the Maple calculator on google play and the app still wont give me more than 5 steps a day. Does anyone know what the problem could be?

How can i get mapple code for solving Fractional Patfial Differential Equation with Laplace, Adomian and New Iteration Method

A system of differential equations

But solution I want to express in terms of other specified function

How to dsolve to get a solution that in terms of a list of specified function? For example in terms of sin , cos , Bessel etc ?

Sol := [a(t) = sin(t) + cos(t) , b(t)= sin(t) ....]

As a Maple user for 10+ years, I've had plenty of stack limit errors, pretty much all of them my fault. But I am currently experiencing a very unusual one after updating my Mac from Maple 2019 to Maple 2021.2.

I am running a long script to fetch json data from a url, parse it, and do a bunch of analysis. In most cases it works fine, but some cases give either an "Execution stopped: Stack limit reached." error, or the error "Error, (in type/polynom) result from type `algfun` must be true or false". Both are being caused by calling the gfun:-ratpolytocoeff command.

I kind of think some internal memory of Maple is being accidentally overwritten because I can cause the error to occur or not occur by adding / commenting out random lines of code that have nothing to do with the part of the code causing the problem. I've managed to find a fairly small script that causes the problem to occur:

with(PolynomialIdeals):
url := "https://api.combopal.ru.is/garpur_run/61e5f7acf2e929ff811caad3":

root_func := F[0, x]:

latex:-Settings(useimaginaryunit=i):

data := URL[Get](url):
json := JSON[ParseString](data):
json := JSON[ParseString](data):

debug_solved := (x^5-3*x^4+5*x^3-7*x^2+4*x-1)/(x^5-5*x^4+10*x^3-10*x^2+5*x-1):

debug_gfun := gfun[ratpolytocoeff](debug_solved, x, n);

If I remove ANY of these lines of code, there is no longer any problem, which is very strange because, for example, I'm not using the PolynomialIdeals package anywhere in the script. This particular script works fine on a Linux machine running 2021.0, but yet I am having similar problems on that machine with other cases.

Here's a slightly simpler example in which gfun[ratpolytocoeff] induces a "division by zero" error ("Error, (in convert/fullparfrac/normal_only) numeric exception: division by zero"):

with(PolynomialIdeals):
url := "https://api.combopal.ru.is/garpur_run/61e5f7acf2e929ff811caad3":

latex:-Settings(useimaginaryunit=i):

data := URL[Get](url):
json := JSON[ParseString](data):
json := JSON[ParseString](data):

debug_gfun := gfun[ratpolytocoeff](1/(1-x), x, n);

After the division by zero error, if I press Ctrl+D to close the Maple command line, it prints
"GC Thread signalAbort 0x7000019a5000 Execution stopped: Stack limit reached.".

Is this an internal Maple bug? Is there any workaround? I am pulling my hair out and would be very grateful for any help.

Hello guys,

I want to find exact form of a(t) in following differential equation:

-diff(a(t), t)^2*_C1*6^(-1/(-1 + 2*alpha))*((diff(a(t), t, t)*a(t) + diff(a(t), t)^2)/a(t)^2)^(-1/(-1 + 2*alpha))/(4*(diff(a(t), t, t)*a(t) + diff(a(t), t)^2)*(-1/2 + alpha)) = (6*diff(a(t), t, t)*a(t)^2*alpha + 6*a(t)*diff(a(t), t)^2*alpha + k^2)/a(t)^3

please guide me,

Hi.  I have not been able to find the individual cost of Maple Flow.  How much does it cost?  (in CDN)  Is it inlcuded in Maple?

Can Maple Flow be installed on Linux?  If not, will a Linux version be released on the future?

Regards

Download stochastic_integral.mw

Has someone tried to connect Grasshopper with Maple yet?

Grasshopper is a visual programming environment on Rhino.

https://en.wikipedia.org/wiki/Grasshopper_3D

Dear esteem Colleagues,

Please how do I modify the following two files (though similar) to get consistent errors? I am not sure where I made the mistake.

Any modifications would be appreciated.

Thank you all for your time and mentorship. Best regard

Biratu_Mapleprimes.mw

DDE_2_Mapleprime.mw

Download contourintegraal_vraag1.mw