Hi

I have been making a 3d graph of the level sets of a function. Here is the code for the 3d graph:

display(seq(seq(plot3d([i/sin(u), u, j], u = 0 .. 3/2, t = 0 .. 10, view = [0 .. 10, 0 .. Pi/2, 0 .. 10], color = i*j), i = 1 .. 10), j = 1 .. 10))

Each curve is a different level set- and I'd liketo colour them all individually -so people can tell tham appart. Any variation of the code I've made makes each of the curves black.

 

Is it possible to create the operator command : |x| so that it passes x to the VectorCalculus Norm function so that if I write:

>  | < 3, 0, 4> |

the result is 5?

I have a Maple program and i need to call a python script with a specified input (10 integers). The script returns a number that I would like to use in my Maple program afterwards. This is what I would do in shell:

```

result=`python model.py 1 2 3 4 5 6 7 8 9 10`
echo $result

```

Is there a way to get the `result` using Maple? I checked the documentation for Maple and it is not very clear so I appreciate any help on this. Thanks!

Hi,

From a previous calculation, I got the following nested sum:

Sum(Sum(f[n]*g[q-n]*exp(2*i*Pi*q*x),q = -infinity .. infinity),n = -infinity ..
infinity)

However, to keep on the calculus, It is more convenient to have:

Sum(Sum(f[n]*g[q - n]*exp(2*i*Pi*q*x), n = -infinity .. infinity), q = -infinity .. infinity)

That is, permute the summation precedence.

Is there a way to automatically transform the first expression into the second one?

Hi everyone,

When my cursor is on an output, the paragraph style changes to 2D Output, as it most likely should. When I then go to a new executable line, it takes forever for all of my expressions to "light up" (meaning that it takes a while for me to be able to use them), and it takes forever for the paragraph to go from 2D Output to 2D Math.

I sadly don't remember when this happened, or what might have caused it, but if any of have any suggestions or answers, I'd greatly appreciate it.

Thanks for listening,

A confused highschool student.

Hi,

I discovered that the option legend, when used in plots:-inequal, returns an empty graphic.
Is it a bug or a deliberate choice?

Anyways, is it possible to insert a legend in a simple way (that is without using textplot for instance)?

TIA

Application of MapleSim in Science and Engineering: a simulationbased approach

In this research work I show the methods of embedded components together with modeling and simulation carried out with Maple and MapleSim for the main areas of science and engineering (mathematics, physics, civil, mechanical etc); These two latest scientific softwares belonging to the company Maplesoft. Designed to be generated and used by teachers of education, as well as by university teachers and engineers; the results are highly optimal since the times saved in calculations are invested in analyzes and interpretations; among other benefits; in this way we can use our applications in the cloud since web technology supports Maple code with procedural and component syntax.

FAST_UNT_2020.pdf

kinematics_curvilinear_updated_2020.mw

Lenin AC

Ambassador of Maple

I'm fairly new to using Maple and am having a bit of a hard time calculating the following inner product. Firstly, I define the tensors (which to this end I'm not certain they are correctly defined), 

with(Physics):

Setup(mathematicalnotation=true)

Setup(coordinatesystems=spherical):

ds2 := - dt^2 + a(t)^2 /( 1-k*r^2)*dr^2 + a(t)^2*r^2*dtheta^2 + a(t)^2*r^2*sin(theta)^2*dphi^2;
Setup(coordinates = spherical, metric = ds2);

e[mu, `~nu`] = Matrix(4, {(1,1)= a(t)/sqrt(1-k*r^2), (2,2)=a(t)*r, (3,3)=a(t)*r*sin(theta), (4,4)=1}, fill=0); (15) 
Define((15))
f[`~mu`, nu] = Matrix(4, {(1,1)=sqrt(1-k*r^2)/(a(t)), (2,2)= 1/(a(t)*r), (3,3)=1/(a(t)*r*sin(theta)), (4,4)=1}, fill=0); (28)

Define((28))

Thus, I defined two mixed tensors e[mu, `~nu`] (one covariant and one contravariant index ) and f[`~mu`, nu] (one contravariant and one covariant index).

Then, I try to take the following inner product between the two mixed tensors and the Christoffel symbols of the second kind, namely,

e[nu, `~alpha`].f[`~sigma`, beta].Christoffel [`~nu`, sigma, mu];

where I used the Physics['.'] command . However, when I try taking this inner product, it returns unevaluated.

Did I define the mixed tensors incorrectly? Does it matter how you define the indices when you're gonna take the inner product? Because taking the inner product of simply e[mu, `~nu`].f[`~mu`, nu] also returns unevaluated. Also, I should mention that  e[mu, `~nu`] and f[`~mu`, nu] are inverses of each other, is there any way to define one and get the other, since, simply changing the way in which the indices are raised and lowered doesn't take the reciprocal of the components. 

Do you agree this solution given by Maple is not correct?

restart;
pde := diff(u(x,t),t)+diff(u(x,t),x)=0;
bc  := D[1](u)(0,t)=0;
ic  := u(x,0)=exp(-x^2);
sol:=pdsolve([pde,ic,bc],u(x,t)) assuming x>0,t>0;
pdetest(sol,pde)

Result of pdetest should be zero.

I think the PDE itself is not well posed (I copied it from different forum to see what Maple does with it). But still the solution clearly does not satisfy the PDE itself for x not zero. 

Maple 2019.2.1 with Physics version 573

test.mw

I am not sure why I cannot do: plot3d([f(x,y,'g(x, y)')], x=0..1,y=0..1).

And the use of single quote in Maple 2019 and 2017 are giving different results. that is, the plot (note, not plot3d) results in the attched script by Maple 2017 and 2019 are different...

Bonjour,

Comment écrire les composantes d'un vecteur contravariant avec des indices numériques ? Ce vecteur n'est pas un spacetimevector.

Par exemple : <x^1, x^2,x^3> avec cette écriture maple interprète ces indices comme des nombres et non comme des symboles

Merci pour vore retour

I do a calculation o a simple integral

      int(cosh(cos(2*t)), t = 0 .. 2*Pi)

and get the answer 0 (zero), which I know is incorrect. The cosh function of a real argument is always positive.

If I represent the cosh function as a sum of two exponentials

(1/2)*(int(cosh(cos(2*t)), t = 0 .. 2*Pi) + int(cosh(-cos(2*t)), t = 0 .. 2*Pi))

I get    

2*Pi*BesselI(0, 1)

which looks much better.

What's the matter? Why Maple yields two different results? Victor.

Hello, Probably there is a way to do this easily but I do not quickly find it within the help.

I want

rand(0..1)

to give a true! random number and not always the same number; otherwise it should be called

predefinedlist()

Seed is deprecated, not sure it would help though. So how do I go abouts?

I went to save a file in Maple and it had large amounts of calculated data. 

Maple didn't ask me if I also wanted to save that data like it usually does - it just saved it.  Saved a 13Mb worksheet that took 5 minutes to relinquish control on my laptop. 

The function evalf(  ) will encounter a critical bug when doing the following evaluation:

restart;
P1 := 1007;
P2 := 1014;
P3 := 1014.1;
evalf(P2 - P1, 2);
evalf(P3 - P1, 2);

The first evalf( ) returns a correct value, while the second one returns a wrong value.
This is really unbelievable!