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Hi all,

I google and found a program using C# connect with Maple. The Maple file is mla file - a pakage library type of Maple. I want to review data structure and all interfaces funtions to understand the way to implement this features.

Please help me the way to read the original Maple code. I uploaded the .mla file into mediafire if you want to review it. Link 


Quan Nguyen

Hi there,

I'm trying to simulate an stochastic SIR model following the Gillespie algorithm, as described here [1].


When trying to update each process' probabilities, it looks like Maple is not updating their values. Although each element of the lists S, I and R is updated the ai lists are not updated.

For example, for a given index i

a2[i]:= m*S[i]:

takes the same value for every i, regardless of the value of S[i].

Can anybody tell why this is happening or what's wrong with the worksheet? This is the attempt:


On the other hand, I tried making things more clear through a couple of procedures. However, when it comes to the point where a random number with an exponential distirbution is computed:

Rexp := RandomVariable(Exponential(mu)):

it looks like Maple is unable to evaluate mu. But having a look at the Variables explorer, it has a defined value, indeed.

So what's wrong in the worksheet? Thi is the attempt:





Hi every one.

I want to export some plots from maple as images in ".jpg" or ".png" formats. I was wondering that is there a way to specify the resolution of the exported pictures? I need high quality pics.

I just bought Maple Student edition. I won't allow me to validate myself and won't allow me to install the software unless I remove Java 8 and install the much older Java 6?!

Please help.

Hi! when i'm trying to solve, i get the following warning: Warning, solutions may have been lost.

The equations i'm trying to solve are as the following:


> D=0.19;

> eqns:={y^1.5-9/8*B^0.5*y+3/4*x*y^0.5-3/4*(Pi/3)^0.5*[1+(1+3/4*(Pi/3)*(B*(1+x^2))^0.5)*x^2]/(1+x^2)^0.5=0, Pi/2-3*D=8/3*y^3+x*y^2+4*B^0.5*[1/3*B*y^1.5-2/45*B^2.5-3/2*y^2.5]-9/2*B*(1/3*B*y-3/40*B^2-3/4*y^2)-3*x*B^0.5*[1/3*B*y^0.5-1/7*B^1.5-1/2*y^1.5],B=A/(1+x^2)};

> vars:={x,y,B};

> solve(eqns,vars);

Warning, solutions may have been lost

What am i doing wrong?

Many thanks!

Hi, all

I use INT to calculate multiple integration as below. It runs more than 20 hours without results. I wander is there any problem in my codes.

A := sin(k*Pi*(x-h*cos(theta))/a)*sin(l*Pi*(y-h*sin(theta))/b)*sin(k[0]*h)*sin(k*Pi*x/a)*sin(l*Pi*y/b);

W := evalf[5](int(int(int(int(A, h = 0 .. (x-a)/cos(theta)), theta = Pi+arctan((b-y)/(a-x)) .. 3*Pi*(1/2)), x = 0 .. a), y = 0 .. b, numeric))



Why the disparity in the solution of P1 and P2? P1 uses finite difference while P2 uses midrich.

See them here     and


What is the combination key for zooming in/out on a Maple 3D graphic?

It seems I have forgotten... (CTRL+left mouse button does not work)





  Suppose I would like to use writedata for a series of files, e.g. test1.txt, test2.txt, test3.txt.  

I tried



for i from a_min to a_max do
  for j from b_min to b_max do 
  end do;
end do;

for i from 1 to 3 do
end do;


Seems "||" inside `` does not work, is there any robust solution for this issue? 


Thank you very much


I am trying to define a new typt and I am beating my head against the wall...

What I have working:

This defines a type which I can then use in type(xpr,Element) to be false or true depending on whether xpr is a record containing (at least) entries l and R or not.

Now I want to define a type ExpandedLine that is a Vector of Element (Element in the sense above). In fact, in the context of my application I am willing to settle for ExpandedLine being a Vector of record.

Tried various approaches (and making sure Vector is in uneval quotes in the AddType statement) like:


and variations but no luck.

Any help is appreciated.

Mac Dude


I want to put the solution obtained from ShowSolution() command of Student[Calculus1] into my LaTeX file. How I can achieve that?

I succeeded in getting latex of ExpandSteps because it was a module, but ShowSolution() is not a module.

Hello everyone,

I have nonlinear partial differential equations (see the attached file) need to be solved:

With initial condition: h(x, y) = K1 (constant), dh/dx = K2 (constant); dh/dy = K3 (constant); And h(x,y) is function of (x,y) other factors are constant. Could anyone tell me how to solve these equations by using numerical method? Do you know any library in c/ c++ language that can solve these equations??

I have tried with Maple 17 and the response is: "Error, (in pdsolve/info) first argument is not a differential equation". Whole of my input:


with(PDEtools); declare(U1(x, y), U2(x, y), U3(x, y));

PDEs = [diff(U1(x, y), y) = U2(x, y),

diff(U1(x, y), x) = U3(x, y),

(diff(U2(x, y), y))*((L-U1(x, y))^2+(D2+tan(alpha)*(L+U1(x, y)))^2)+.5*U2(x, y)*(2*tan(alpha)*U1(x, y)-D2) = 0,

(diff(U3(x, y), x))*((L-U1(x, y))^2+D1^2*cos(alpha+2*U2(x, y))^2)+.5*U3(x, y)*D1*cos(alpha+2*U2(x, y))+.5*D1*sin(alpha+2*U2(x, y))*(L-U1(x, y)) = 0];


[ d d / d
PDEs = [--- U1(x, y) = U2(x, y), --- U1(x, y) = U3(x, y), |--- U2(
[ dy dx \ dy

\ / 2 2\
x, y)| \(L - U1(x, y)) + (D2 + tan(alpha) (L + U1(x, y))) /

/ d
+ 0.5 U2(x, y) (2 tan(alpha) U1(x, y) - D2) = 0, |--- U3(x, y)
\ dx

\ / 2 2 2\
| \(L - U1(x, y)) + D1 cos(alpha + 2 U2(x, y)) /

+ 0.5 U3(x, y) D1 cos(alpha + 2 U2(x, y))

+ 0.5 D1 sin(alpha + 2 U2(x, y)) (L - U1(x, y)) = 0]

Error, (in pdsolve/info) first argument is not a differential equation


I will be very appreciated with your help!!!

I need to convert a base 10 int(defined as num) to its base 3 format using a while loop. I would like to store the remainder of the num%3 to a list/sequence/array in maple. Now, if I were to use a sequence, I would need a pre-defined range. How do I solve this issue?

I've got a piece-wise function(for which I've made the procedure) f defined over x<=-1, -1<x<1 and x>=1 which I am trying to plot over the range of (-2,2). I've tried using plot(f,-2..2) but it doesn't show any curve. Should I add a few more parameters to plot()?

I've got the following lists :

list1:=[1, 5, 14, 30, 55, 91, 140, 204, 285, 385, 506, 650, 819, 1015,

1240, 1496, 1785, 2109, 2470, 2870]
list2:=[1, 5, 14, 30, 55, 91, 140, 204, 285, 385, 506, 650, 819, 1015,

1240, 1496, 1785, 2109, 2470, 2870]

each generated by a procedure I defined. I need to verify that they are equal, which is the case. However, when I tried to use the evalb function as well as a flag that I was updating during a loop, in both cases, I got 'false' as  the answer along with the error message: 

"error, final value in a for loop must be numeric or a character"

What I am doing wrong?

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