## How do I create a function using define_external?...

Hi! I have an external library with this function: ``` double test(double x) { return sin(x); } ``` In Maple I am doing this: test := define_external('test', x::(float[8]), RETURN::(float[8]), LIB = "Test.dylib"); f := x->test(x); Now when I call f(2) for example, I get 0.909297426825681710 back. But if I try this: plot(f(y), y = 0 .. 2); I get this error message: `Error, (in f) invalid input: test expects its 1st argument, x, to be of type numeric, but received y` I think I need to somehow convert the (possible) symbolic input of f into a float[8] before it is passed to the procedure test, but I can't figure it out.

## Plotting surfaces in Maple with constraints...

Dear All, Does anybody know how to plot a surface in 3d with only those points which satisfy a constraint? In particular I'm plotting the surface defined by the equation F(beta,Omega,delta)=0 using implicitplot3d. Unfortunately, I want to command Maple to leave out any points which violate the inequality h(beta,Omega)>0. Does anybody know how to do this? cmichael

## Enumerate all minimal cut sets in the graphs...

Dear Sir or Madam, There is a maple code below for finding all paths between two given pair of vertices. Is there any maple code available for finding all minimal cut sets ( i.e., components whose failure will results in a network failure) between any given pair of vertices? For example, a bridge network: >with(networks): >G:=graph({1,2,3,4},{{1,2},{1,3},{2,3},{2,4},{3,4}}): Question: Find all cuts between node 1 and node 4. Doing it by hand, I got: [{1,2},{1,3}],[{2,4},{3,4}],[{1,2},{2,3},{3,4}],[{1,3},{3,2},{2,4}]. It is not easy to enumerate all cut sets by hand when the network is large. How do I code it in Maple??

## applyrule with proc()...

Hello, I have expressions of the form `e[i,j,k]:= s*U(s)*a(s,y,z,t)+ s*(s+1)^2*b(s,y,z,t)+ ...` where `e` is a symmetric array, i=1..4, j=1..4, k=1..4 and function a(s,y,z,t),b(s,y,z,t),c(s,y,z,t),f(y,z,t),g(s,y,z,t),... and their partial derivatives are appearing in these expressions I exracted different coeff, named them, and then I wanted to rewrite each e[i,j,k] while substituting coeffs with implicit function, so I've used `applyrule` in a procedure but not all coeffs are substituted. Can anyone help please. Here is my worksheet View 4780_beny1.mw on MapleNet or Download 4780_beny1.mw
View file details

## plotting functions of solutions of an ODE system &...

Hello!

I use Maple 9 for some weeks and it helps me a lot. In the last days I have 2 problems that I could not implement in Maple. I spent many hours reading manuals, tips etc. without finding an idea, so I decided to post here my questions:

I use dsolve (numeric) to solve a system of ODEs. I receive the solution "p" wich I can plot whithout problems.

Question 1
----------

After this, I define a new function "S" as:

S := t -> p(t)[2] + p(t)[3] + p(t)[4] + p(t)[5];

I tried to plot it with

e:=1.5;
interface(plotoutput="sum.ps");
plot(S, 1..e);

## Creating a scatterplot from two columns of data fr...

I am trying to import data from Excel and re-create the scatterplot that is on the Excel spreadsheet. The first column contains the Y data. The second column contains the X data. I can import and browse the array of data but I cannot create a scatter plot of the data. I want to fit a function to the data and overlay this function on the graph to visually see how well the fit is. Thanks.

## Manipulating the output of the solve/fsolve functi...

Hello, I would like to know how i could manipulate the output that i receive from the solve/fsolve commands: sample code: > for n from 1 to 10 by 1 do > fsolve({x+y=n+6,x*y=10},{x,y}) > end do; {y = 2.000000000, x = 5.000000000} {y = 1.550510257, x = 6.449489743} {x = 7.701562119, y = 1.298437881} {x = 8.872983346, y = 1.127016654} {y = 1.000000000, x = 10.00000000} {y = 0.9009804864, x = 11.09901951} {y = 0.8210916542, x = 12.17890835} {x = 13.24499800, y = 0.7550020016}

## Commutative Matrix Multiplication...

Does anyone know how to do commutative matrix multiplication ? I'm doing a worksheet with the classic worksheet of Maple 10. To clarify further, I just want to multiply corresponding elements of two square matrices, NOT multiply the matrices using the proper rules of matrix multiplication. respectfully, Dan

## Running Maple under Fedora Core 6...

We hav a version of Maple 8 which is still running on our department machines which is currently running a version of RedHat Enterprise Linux 3 or 4. At home I've been using Fedora Core. I managed to keep Maple 8 running up to Fedora Core 3. To do so, I had to relink libc.so.6 in /usr/local/maple8/bin.IBM_INTEL_LINUX to a copy of libc.so I copied from a department machine. I've now installed Fedora Core 6, and that arrangment doesn't work. maple gives the error message /usr/local/maple8/bin.IBM_INTEL_LINUX/cmaple: relocation error: /usr/local/maple8/bin.IBM_INTEL_LINUX/libc.so.6: symbol _dl_out_of_memory, version GLIBC_PRIVATE not defined in file ld-linux.so.2 with link time reference

## Howto do abstract algebraic equations?...

Hi, First of all, I'm quite new to Maple and here, so I hope you will be patient with me..ehhehe. I've been struggling some days creating abstract vectorial equations with no luck. The equations have vectorial components as well as a matrix, it is the equation of motion, i.e: Inertia * dw/dt + w x Inertia.w = T Inertia is a matrix that I dont want to define now, and most of all I dont want to spread out its components, so it has to be all the time "Inertia". w is a angular speed vector and T is the Torque vector. Neither I want w to be defined or component separated (wx,wy,wz) at this point since I need to work with w for some change of coordinates .i.e w = w1 + ww1 . So I need to work in this abstract level.

## Changing exported GIF resolution from 96 dpi...

The default dot density for exported GIF files is 96 dpi - necessary for screen display but not optimal for printing. Is there anywhere, internal or external to Maple 11, to monkey with the resolution to suit me? (Obviously, I can export GIF and then "alter" resolution in a third party package, but, hopefully obviously as well, this doesn't help as it is very lossy. I need to save the vector content directly to, say, a 200 dpi GIF image). Also, wmf and eps format exportations are not good options for me either, as these two file export formats fail to reproduce the graph I see on my Maple document: layering gets scrambled, transparency settings are ignored or altered, etc.

## Simplification of random variable distributions...

Hello, I have a question and really appreciate for any input: - I define an exponential distribution function called f(t) - Then, I define RP2(t) as a piecewise function of random variable t and some constant parameters. - I would like to parametrically derive Expected value of RP2. I can easily derive it on paper, given exponential distribution of f(t). - However, in Maple 10 as its file has been attached, I get the piecewise results without any simplification. Even simplify command yields the same results. I don’t know what I am missing. Any input is highly appreciated. Best regards,

## creating a loop...

Hi.. been using maple v.10 for a few days now.. I created a maple sheet for newton's method of approximation.

The aim was to find F(x) = 0, my final value for Xo was −1.509410457

I wanted to know, how to create a situation where Xo is continuously replaced with Xnew until Xo = Xnew.

Here's my code:

> restart;

> Xo:=-2;

> F(x):=(Xo^5) + 3*((Xo)^2)+1;

> dFx:=5*((Xo)^4) + 6*(Xo);

>

>

Xo := -2

F(x) := -19

dFx := 68

> Xnew:=Xo - ((F(x))/dFx);

.............-117
Xnew := ----