Hi

I have the following of fractional of ode system.

.How to solve it by maple.

Professor Robert J. Lopez is a Maple Fellow and the author of many Maple webinars and applications. He is also co-author of a book entitled Discovering Calculus With Maple, which I have recently acquired, and which turns out to be keyed to Maple V Release 3 on a Mac. Well, I have Maple 2020 on a Mac. What is the best way to get this book to work for me?  Thanks very much.

Hello, 
I have this problem to my system:

sol := pdsolve(sys2, {bcs, ics}, numeric)
sol:-plot3d(u1(x, t), x = 2 .. 3.2, t = 100 .. 1000)
Error, (in pdsolve/numeric/plot3d) unable to compute solution for t>HFloat(0.0):
unable to store HFloat(undefined)+HFloat(undefined)*I when datatype=float[8]

It is 1 pde and 1 ode.

What can I do to solve it?

Best
 

Hi

I am trying to construct a controler for a UR5e robot, I have a simulation of the robot in maplesim and have started to look for a way to use multibody analysis to provide me with the Jacobian. However it only provieds the constraint Jacobian and as I have no position constraints on the robot, it returns nothing.

I then came across 

Link: https://www.youtube.com/watch?v=d3xJge_09E0&t=374s

However it is old and does not exactly say how to do it.

So I thought I should ask this wonderful comunity if they have an recomended way to construct the Jacobian from a maplesimmodel? I am still a beginner at maplesim and maple so any help is appreciated.

With thanks for helping me

Eric Ragnarsson

Is it possible to develop a code for base excitation problem where excitation data is of earthquake acceleration?

p.s. There are 12000 data available in EQ file.

Hello Everyone,

I am currently trying to tidy up my worksheet and hide all of the script/code that I wrote in the Maple 2D-Math within the execution script of buttons etc.
Was going well so far until I started transferring code where I was using a lot of symbolic math (if I understood correctly)
There is one instance where I have a variable chi which equals x divided by a.
a being a number, e.g. 5000, while x is and remains a variable.
No problem in 2D-Math as the unknown x is dragged through all following equations.

Not so in the code editor, I think. Doing the calculation results not in x/5000, but in this:


It keeps getting worse because this term will be derived, assembled into a matrix, etc. where the expressions are getting ridiculous:


Without getting into the details of what my script should do, I believe this is a very general issue, not specific to my code.

Is the code editor / "Code when Used/Clicked" not capable of symbolic math? Oder is there some setting that could potentially help me?

Best Regards,
Lennart
 

Hi,

I try to build a trigonometric circle with particular values Pi/6,Pi/4,Pi/3, but I find that the coordplot command with its options do not react .

Ideas ? Thanks

CercletrigonométriqueMaple.mw

Hi

I am trying to create a simulation of a UR5e, I have added a spring dampening systen in order to simulate the imput of external forces and torques. However I get a strange error for which I could not find an awnser for on the web.

The closest was 

https://www.mapleprimes.com/questions/203860-Compile-Maplesim-Model-To-Ccode

However it is quite old and not entirely a match. 

I get the following output

More information

Maplesim 2020

64 bit version

Windows 10

RAM - 16 GB

Do anybody know a solution for this?

Mvh

Eric Ragnarsson

Hi,

I can’t block the display of my p and A variables even if I finish my commands with both points.

Ideas? ThanksTrianglesQuelconques.mw

Hi all,

There is issue with modp1(('Embed')(...)) function.

Please look at the file:

bug_embed.mw

As you can see in lines 1, 3, 5 Embed function in combining with Constant cutting several digits from argument.

Thank you.

Hi, 

A year ago I submitted a problem about the sampling of a Gaussian Random Variable (GRV).
A serious problem with Statistics:-Sample()
In short, the default method (Ziggurat method) used in the Stratistics package to sample a GRV overestimates the weights of the tails of the distribution.

Forcing the method to "envelope" is a way to obtain a correct sample

Statistics:-Sample(Normal(0, 1), N, method=envelope)

(another one is to use for instance the Box-Muller sampling algorithm ; look to the reference above for the fast implementation acer proposed).

I recently observed that the envelope method generates an error ("too many inflexion points...") when the standard deviation of the GRV is not one.
I tried to avoid this error by adding the suboption "range" :

restart:
f := (sigma, k, N) => Statistics:-Sample(Normal, 0, sigma), N,  method=[envelope, range=-k*sigma..k*sigma]):
# this works
f(1, 3, 10):
# these do not work
f(0.1, 3, 10):
f(10, 3, 10):

Here, k is a positive real value (which could depend on N but can be imagined to be around 5 or 6 to fix the ideas
Even with this suboption I keep receivind the same error.

If there is no way to parameterize correctly the envelope method, this means that Maple is unable to sample correctly a GRV.

Of course, if X is a GRV of mean mu and standard deviation sigma on could do this to generate a sample of X:

Xstd := RandomVariable(Normal(0, 1)):
Sstd := Sample(Xstd, 10^6, method=envelope):
S := mu +~ sigma *~ Sstd

But this should not be a permanent solution.

second has rsolve solution

compare original sequence

accsum(ListTools[Reverse]([seq(patterngroup[k], k=(mm)..(mm+lengthofsequence))])),

with rsolve solution , it start from third number wrong, some number are wrong but correct at next number, 

but i just want to guess next number is 1 or 2

[seq(subs(k=kk, sol), kk=0..(lengthofsequence+1))],

with(SumTools):
with(gfun):
accsum := proc(xx)
local result,mm:
result := []:
for mm from 1 to nops(xx) do
temp := Summation(xx[k], k = 1 .. mm):
result := [op(result), temp]:
od:
return result:
end proc:

patterngroup := [2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1]: # left is latest, 2,1,1..
lengthofsequence := 5:
for mm from 1 to 12 do
if guessgf(accsum(Reverse([seq(patterngroup[k], k=(mm)..(mm+lengthofsequence))])), x) = FAIL then
print(patterngroup[mm]):
else
sol := rsolve(listtorec(accsum(ListTools[Reverse]([seq(patterngroup[k], k=(mm)..(mm+lengthofsequence))])), u(n))[1], u(k)):
acxxc := accsum(ListTools[Reverse]([seq(patterngroup[k], k=(mm)..(mm+lengthofsequence))])):
olist := [seq(patterngroup[k], k=(mm)..(mm+5))]:
#start from 0
print(patterngroup[mm], olist, accsum(ListTools[Reverse]([seq(patterngroup[k], k=(mm)..(mm+lengthofsequence))])), [seq(subs(k=kk, sol), kk=0..(lengthofsequence+1))], sol, subs(k=(lengthofsequence+1), sol), subs(k=(lengthofsequence+1), sol)-acxxc[nops(acxxc)]):
end if:
od:
 

Hello all

I wanna solve an optimal control problem and I have searched the Internet but I could not find any tutorial or video course on how to solve it with the Pontryagin maximum principle method. It is my first time that I want to use MAPLE for solving an optimal control problem and I would be thankful if someone can help me.

$$\max \int_{0}^{1} x_{2} [u(t)-u(t)^2] dt        $$

$$  \dot{x}_{0} = -(1-u(t)) x_{0}(t)+2 x_{1}(t) $$

$$  \dot{x}_{1}(t) = (1-u_{t}) x_{0}(t) +2 x_{2}(t) -[3-u(t)]x_{1}(t)  $$

$$   \dot{x}_{2}(t) = (1-u(t))x_{1}(t) -2 x_{2}(t)   $$

$$  0 \le u_{t}  \le \frac{1+t^2}{1+t}  $$

Thanks

Given a lagrangian  in general relativity , how can I calculate equation of motion using euler lagrangian equation in maple software ?

the lagrangian is 

L = 1/2 g[mu,nu] diff(x[~mu], lambda) diff(x[~nu],lambda)

here lambda is the affine parameter.  and the metric is 

metric coordinate = (t,u,x,y)