Hello,

I seem to be having trouble with the define_external command.

I want to call a C-library from maple, and I think I need to convert the maple data in C. So I need a custom wrapper.

But I can't get the simple example from here to work for me. Specifically, I tried this:

I am having trouble getting an algebraic solution for a first order four-ODE system. The problem seems trivial to me. However, Maple is taking a very long time to solve it. The system describes a reversible "chemical" reaction that have 4 states. Basically, the system is

C1<->C2<->C3<->O1

where the rate constants are ai towards the right and bi towards the left.

Any suggestion will do.

Thanks!

Hello all,

I have a question about converting a continuous piecewise function to Heaviside function, which the function includes trunc() in its conditions.

(I found differentiating piecewise function gives me "undefined" at boundary)

When I do that operation (convert(piecewisefunc, Heaviside)) I get the error below.

"Error, (in piecewise/simprootsstep) cannot determine if this expression is true or false: 0 < 183.3333333*Pi"

In the simplest case I could find of this...

How do I get Maple to simplify: sqrt(x.y)/x.y  to  1/sqrt(x.y)

?

If I remove any one of the 4 factores out of the equation above, it will just do it, but with the 4 together I just can not get it to give it to me in a "sensible" form.

Tx

Max

Hello,

suppose I have a huge polynomial in several variables, say x, y and z, with some unknown coefficients:

(a*b+1)*x^3+(a+b+1)*x^2*y^2+(a-b^3)*x*y^2+a*y^10

Is there an efficient way to obtain all coefficients, when interpreting this as a polynomial in x and y?

(My goal is to make maple solve the equations in a and b  in order to let the polynomial be identically zero)

Many thanks!

Dear Maple users

I am looking for easy ways to manipulate lists. Especially I want to take a list of lists, say:

[[1,3], [5,8], [9,2], [5,12]]

and create a list of the second components:

[3,8,2,12]

Another problem: How do I collect every second element of a list, say:

[4,2,-1,9,5,6,2,0,14,7]

creating [2,9,6,0,7].

I can do it with loops, but I guess there is a smarter way to accomplish these tasks. I was looking...

I noticed, that FileTools[Text][ReadLine] cannot read Cyrillic letter "я" in text files.

My test file containes 6 lines (Codepage 1251):

 Николай Петрович ТРУБЛАИНИ
 "ЛАХТАК"
 Ч А С Т Ь П Е Р В А Я
 НЕМОЙ ПАРОХОД  Г л а в а I
 Ветер налетел неожиданно. С неимоверной быстротой запенились волны. Они приближались к пароходу, стоявшему в миле от берега. Между реями мачт и в надстройках...

Hello everyone!

I have a small problem with setting of name's variable by using for do loop!

Small description of the issue: i have a loop which looks in that way:

for k from 1 to 4 do

y'k':=Matrix[a,b];

end do;

Еventually i want to have, for instance, four matrices with different filling but ranged from 1 to 4:

y1:=...

y2:=...

...

Especially i want to see names of the variables in the abovementioned way i.e. y1 and not y[1]!

I tried the following, but did not get 0. Why not?

>restart;

>b:=3*beta*Pi*(3-4*cos(z)+cos(2*z))/(16*z);

>-b+sqrt(b^2)

I know I can do this by hand, but this is part of a larger equation which I narrowed down to this issue.

Hi,

I am having some problems when solving NullSpace when the matrix is somewhat 'complicated'.

Maple seems not able to find the nullspace.

Any hints or possible workaround?

Casper

nullspa.mw

Hi all,

I 've been using Maple 13 and recentely upgraded to Maple 17. But the following code yielded correct results in Maple 13 but not in Maple 17( gives an error: there is no taylor series expansion, try series).

I think there is some bug or some problem with "mtaylor" of Maple 17. Can anyone verify this?

CODE:

=================

> restart;
> with(VariationalCalculus);
>
> interface(prettyprint = 3);
> with(LinearAlgebra);

Hello to you all. Pls. i just want to ask you guys about which package in maple can I use to solve nonlinear ODEs Also, can I use the Newtons Method?

Iwould like to calculate the inverse laplace transform of the expreesion which I call T.

< T:=tanh(s):

To do this I use the code "invlaplace" to solve it.

<invlaplace(T,s,t)

But it returns "invlaplace(tanh(s),s,t)".Done nothing.How to get its mathematical expression? I am really interested to get it.

PLZ help me in anyway as you can as I am completely stuck.

I wrote a procedure which rounds floats to a specified precision. I would like to apply it to a Matrix/List/Array/Vector that contains non-numeric cells as well as floats. I'm stuck at the type-checking stage.


# Round0 works on floats and lists and Matrices of floats:
restart;
Round0 := proc(x,n::integer:=1)
   parse~(sprintf~(cat("%.",n,"f"),x));
end proc:

Round0(1.23456789);
1.2

Round0([1.23456789,9.87654321],2);
[1.23, 9.88]

Hello,
I'm trying to write a function which is calculating a B-Spline Function. Given is a knot vector U=[u₁,...u_m]. What i want to calculate know is the basis function of degree 0 which is defined by N_i,0(u)=1 if u_i <= u < u_i+1 and 0 otherwise. I tried to do this with two procs which are leading to the same problem:
procVec1 := proc (U)
m := nops(U);
N := [seq(0, i = 1 .. m-1)];
for i to m-1 do