Maple 2018 Questions and Posts

These are Posts and Questions associated with the product, Maple 2018

Hi

I would like to designate AU as currency for my application, rather than the USD.

I can do it to a degree, but when I use combine I have problems. Compare output 8 and 9 to 17 and 18. help?

 

CURRENCY.mw

This is from the documentation of ?plot3d,light:

 

light=[phi, theta, r, g, b]

    This option adds [my emphasis] a directed light source

    from the direction phi, theta in spherical coordinates.

 

The "adds" in that sentence seems to imply that

multiple light sources are possible, but it does not seem

to work that way.  Each subsequent light option overrides

the previous one as we see in the following illustration

where we render a ball three times by illuminating it

(a) from the north, (b) from the south, and (c) from

both the north and south.  In (c) Maple accounts for only

the south light.

restart;

with(plots): with(plottools):

ball := sphere(1, style=surface, color=gold):

display(<
    display(ball,light=[0,0,1,1,1])   |
    display(ball,light=[180,0,1,1,1]) |
    display(ball,light=[0,0,1,1,1], light=[180,0,1,1,1])
 >);

 

Download light.mw

 

This is using Maple 2018.2.1 and using Physics version MapleCloud 289 on windows 10, 64 bit with lots of RAM (64 GB). The call to timelimit hangs. Is there a workaround?

restart;

#and in new execution cell

pde :=  diff(w(x,y),x)-((k+1)*x^k*y^2- a*x^(k+1)*tan(x)^m*y + a*tan(x)^m )*diff(w(x,y),y) = 0;
cpu_time := timelimit(180,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'))

 

 

 

 

Hello,

I'm a long-time Maple user and have used the CodeGeneration package in the past, but with a recent download of Maple 2018, I'm now getting an error I have never gotten before. Even when I do something simple (see below, for example), I get an error that reads "Error, (in clear) argument `` is incorrect or out of order". And I get this error no matter which language I choose. Any help would be much appreciated.

> with(CodeGeneration)

> R(exp(x))

Thanks!

 

 

I hope you can help me. I like to use the Workbook feature in Maple 2018. I save variables in one document to use them in another document as well. If, however, the value of the variable changes, I have to delete the variable in the variable manager each time and save it again.
Is there a command I can use to delete and re-save the saved variables?

Hey,

I have just started using Maple for my university project and I am follwing this guide https://www.maplesoft.com/support/help/maple/view.aspx?path=DifferentialGeometry%2FTensor%2FKillingVectors to calculate Killing Vectors. My issue is that when I try and define a metric using evalDG, I need to write dx&tdx to mean the tensor product between the two. Maple interperates this as a neutral operator and gives me "Error, invalid neutral operator".

I am not sure where the issue is as I have written exactly the same code as the guide and yet it gives me an error 3 lines in. Is there some issue that I am not aware of as someone who hasn't used Maple before? Any advice would be useful as I am not really sure how it is possible and I need to be able to write the tensor product to define the metric. 

 

Even for the simplest metric it does not work. My code is:

with(DifferentialGeometry): with(Tensor): with(LieAlgebras):
DGsetup([x, y], M):
g1:=evalDG( dx&tdx):
 

Any help would be greatly appreciated.

 

how I can find solutions for non linear equations.

I want to find non zero solution.

thank you

ZAH.mw



Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/ZAH.mw .
 

Download ZAH.mw

Hi, Maple is totally new to me and I found something confusing.

Here is what I have:

the_first_element:= proc( A:: Array( numeric ) ) ;
A[1];
end proc():

And it shows Error, invalid input: unknown uses a 1st argument, A (of type Array(numeric)), which is missing.

 

But in another similar procedure, I have exactly the same lines but it goes without error. 

locate_max := proc( A :: Array( numeric ) )
if ArrayNumDims(A) <> 1 then
    error "can only search 1d arrays"
  end if:
end proc: 

I have no idea what is wrong with these 4 lines.

Thank you in advance!

I am on a Mac and unable to login to MapleCloud. I can log in perfectly fine via the website in all browsers. Any solutions for this?

 

How to simplify

a*b=a*c

to b=c ?

I have a procedure that changes the value of an input variable quite unexpectdly. Can anyone explain why? I have a very simplified example of this below.

restart;
with(LinearAlgebra):
switch := proc (V::Vector)
description "This procedure is supposed to take a Vector V and switch entries 1 and 2";
local W,a,b;
W:= V;
a:= W[1];
b:= W[2];
W[1 ] := b;  
W[2] :=a;
W
end proc;

V1:=Vector([1,3,5]);
V2:=switch(V1);
I have omitted the output for brevity's sake but all works well as expected.
However,
V1;

returns V2 not V1. Why is the procedure changing V1?
 

The problem occurs with matrices but not with lists.

 

Thanks.

 

Hello there,

for academic purposes I need to solve a pretty complex and substantial non-linear equation system. Here you can have a look at the equations:

kompletter_nachbau_v0.mw

The MAPLE Statement "fsolve" is not working here, though there is no error message. I know, that I can provide a framework for each variable to help fsolve find a solution. But for my usage this is not an appropriate task, since I'd like to do some simulations and variations with the input parameters.

Is there a way, so I can find a solution to my equation system?

 

It would be possible to make some adjustments to my equations, e.g. reducing the complexity of the equations and increasing the number of equations at the same time, if needed.

I would appreciate any advice!

Thanks in advance!

In the worksheet below I produce a sequence of frames for an animation by distributing the task into several threads.  The result has strange artifacts as we see in the sample.  The artifacts vary randomly from run to run.  Am I doing something wrong?

restart;

kernelopts(version);

`Maple 2018.2, X86 64 LINUX, Oct 23 2018, Build ID 1356656`

kernelopts(numcpus);

4

Draw a simple picture:

frame := proc(t)
  plot(x^2 + t, x=-1..1, title=typeset("t = %1", t));
end proc:

Generate a sequence of pictures:

frames := Threads:-Seq(frame(t), t=0..1, 0.05):

Animate the sequence:

plots:-display([frames], insequence);

Download theads.mw

Hi all,

I have a data set (see .txt file attached) to be fit to the model function A*sin(B*x+C)+D. Calculating the parameters A, B, C, and D is easy enough, but is there a way to have Maple return their standard errors?

Data.txt

Hi,

I can’t perform the last command (GridPlot) on my worksheet

 

 

IRISdata.mw


 

 
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