Hi!

I am trying to convert expressions into functions, but the expressions have many variables x1, x2, x3.....xn.
The reason I am doing this is because I am hoping that differentiating functions in a large jacobian with large multivariable functions will go faster with functions than expressions. If it doesn't go faster then let me know.

What I am trying to do in a simplified code,

xv:=Vector(2,symbol=x):
f[1]:=x[1]+x[2];
f[2]:=x[1]-x[2];

f[1]:=unapply(f[1],[xv[1],xv[2]]);

Diff(f[1],x[1]);

                          f₁:=x[1] + x[2]
                          f₂:=x[1] - x[2]
f₁:=(x_1, x_2) -> x_1 + x_2
                            d        
                          ------ f[1]
                           dx[1]     

How can I get this to work? And is it worth it?

Hi everybody,

I use a maplet that contains a DropDownBox named DDB.
This DropDownBox has a list named MyList
I want to replace MyList by a new list named MyNewList

The syntax given in the Maplets[DropDownBox] help page is
Maplets :-Tools :-Set(DDB(itemlist)=MyNewList)

This command returns the error
error in Set, invalid option for  ‘DDB(itemlist)’  ….

Is it a bug or some misuse (in the help page the “itemlist” option is written itemlist* : what is the meaning of this “*” ?)

As always any answer will be greatly appreciated.

I produce a list of permutations with "permute".

For each produced permutation, I want to have its sign (1 for even, -1 for odd).

Is there a command for that? 

Dear all,

I am trying to solve this inequality:

0 < 2*b^2*(10*K*a+3*K*b-sqrt((K+(2*K*a+1)/b)^2-4*K/b)*b+5)

for a.

However, I get to the error below:

Error, (in testeq) invalid arguments
does anyone know which mistake I am making?!!

what is this testeq?!

Pls how can I label my vertical axis in such a way that the label will be written vertically e.g "proportions of Susceptible"

If I pass "a := x + y;"

as a string

can it turn to command?

if so, can it export this feature into c# or python?

Hi all,

I am trying to have the following display correctly....

ans1:=7/9;

ans2:=1/4;

XMLTools[Print](MathML[Export](ans1;ans2);  THIS IS THE PROBLEM LINE:  I know why this is a problem but need a work around.

Essentially I would like to display:  ans1 ; ans2,  i.e with a semicolon between the two answers.

Hi everybody,

I am used to using  the DocumentTools :-RunWorksheet command and I am confronted with the following problem :

• My worksheet is deemed to generate a plot in a png file
  > plotsetup(png, plotoutput=MyFile, …)
  > plot( …)
  But MyFile is not created
   
• Thinking that the mw file launched by  DocumentTools :-RunWorksheet is seen as a procedure, I have thought that print(plot(…)) would fix the issue.
  Unfortunately the png file is still not created (same behavior with a jpeg file)

I know that  DocumentTools :-RunWorksheet is “experimental” but I wonder if I am doing something wrong or if DocumentTools :-RunWorksheet simply does not support plots ?

Thanks in advance

Fix_integrations.mw

Could you any one help me to fix this application and find the result for integrations?

Many thank,

I wrote some procedures in an older version of Maple to sort through a matrix and find repeated elements, and then set the matrix elements equal to one another. As an example, consider the matrix:

Due to its symmetric nature the upper triangular matrix is just the same as the lower triangular. i.e. the elements are equal: (2,1)=(1,2), (3,1)=(1,3) etc...

I have attached a minimal working example Maple script, which processes an input matrix, finds repeats and sets the elements equal to one another (e.g. [1,2]=[2,1], literally printing this) and saves the output to a file using a specific format for processing by another program. The matrix in the file is numeric but the actual matrices contain a lot of algebraic terms and can get quite large. This is where my procedures struggle as they take a very, very long time to process larger algebraic matrices to group the repeats. Is there a more Maple friendly way of going about this problem rather than these "archaic" procedures?

Here is the script:

duplicates_matrix_.mw

Thank you in advance

-Yeti

Dear please check once it showing an error program.mw as intial value is not conververging

proc:=changecoords([x,y],logrithmic);
dsolvediff(x,t):=Matrix([[ 1 , 0],
        [ 0 , i ]])x+Vector[column]([ x^i ,
                 0]);
x:=y+h(y);
for i from 2 to 10;
solve;
end do;

endproc;

     
MakeIteration := proc( expr::algebraic, x::name )
    local iteration := diff(x,t)=Matrix([[ 1 , 0 ],
        [ 0 , i]])x+Vector[column]([ x^i ,
                 0]),x:=y+h(y);
for i from 2 to 10 ;
end do ;
    unapply(iteration, x);
endproc;
Error, missing operator or `;`

Hi , I would like to solve nonlinear equation by using maple,but I wander how I can write it since there is a change of veriable bysubstiuting the value of y in the diifferenitat . Iactually coudnot write the equation sine it contains differential ,matrix and vector . do Ihave to use dalembertian? 

best regards 

Hello,

how can I tell Maple that "u" has the dimension of volts? 

Thanks for every good advice.

Dear MaplePrimes team,

For display a beautiful parametric surface with hole (or pierced surface), unfortunately unlike CAD (computer-aided design) tool, Maple requires a large grid number. Therefore the computing is too long and requires huge RAM only with grid of [500,500] on a modern computer.

Fig. 1: For a complex surface such an aircraft fuselage here, Needs high grid, therefore, the compilation is too long with modern computer (Intel Core i7, 2.4 GHz CPU, 16 GB RAM). If displays supplementary windows holes on fuselage, the software may bug when the RAM is full.

Question 1:

In matter of low cost computation, do you have better solution to create a fast surface with smooth hole from given a parametric surface equation S(x,y) and given any convex/concave-closed parametric curve C(t) that is projected on surface S(x,y)?

Fig. 2: These surfaces are been created in Maple 2016 from given initial parametric surface equation and curve projected on the surface. But requires huge grid, huge RAM, and long time to get smooth hole when free CAD tools are fast and low RAM.

Question 2:

Because I noted that the Maple’s view option renderers smooth edges of any surface. My question is: Is it possible to use the internal structure of display/view used by Maple to apply at free boundaries? I think it will be possible to create many class of view, for examples: cylindrical sector, spherical sector views or more rather to be limited with conventional cubic view. And thus, I think it will be possible to create own smooth hole or multiple-hole on surface and get smooth pierced surface.

I know that almost of technicians/engineers will recommend me to use a CAD tool to create surface with hole. But the objective here is to keep purely a mathematical mind and work with exact equations (analytic equations).

On a free CAD tool, even the complex holes are created very fast only with low RAM. Why not on Maple?

Best.

Guy.

Hi everyone,

as a very basis example I've tried to get the equipotential lines of an 1/r² potential in the x-y-plane using contourplot. However, I obtained the following very strange result. Do you get the same mistake or is there something wrong on my end?

Thanks in advance,
Sören

Download contourplot.mw