emendes

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Hello

Thanks to the help of several list members I managed to translate and update some old procedures.  These procedures were part of a packcage and they all had help files.   Here is an example

 

# E. Mendes - 25/04/94

`help/text/sampling`:=TEXT(``,
`FUNCTION: sampling - finds the discretized model`,
` `,
`CALLING SEQUENCE:`,
` sampling(f)`,
` sampling(f,k)`,
` sampling(f,k,vars)`,
`PARAMETERS:`,
` f - state space`,
` k - order of approximation`,
` vars - variables`,
``,
`SYNOPSIS:`,
`- sampling(f,k) returns a discrete approximation for a continuous`,
` system`,``,
` dx(t)/dt=f(x(t),u(t)) `,
``,
`EXAMPLE: `,``,
`> with(linalg):`,
`> f:=vector([x2,x3,-x1+x2^2+2*x3]):`,
`> sampling(f,1)`,
``,
` 2`,
` [- x1, x2 + x1 ]`,``,
`SEE ALSO: fixpoind, fixpoinc`):

 

I have browsed the help documentation but I must confess I don't feel comfortable to modify the help database.  Do I have to wrap all the functions up as a package and then write the help files?   I am lost here.  Any help will be most welcome.

Many thanks

 

Ed

 

Hello

I am working my way back to use Maple for some calculations I did in the past.   ListTools seems to have some of the functions I need but I couldn't find anything that gives me the position of all groups of repeated elements in a list of a list.  For instance, ListTools:~MakeUnique removes the copies of all repeated elements but it seems that there is no counterpart function that gives the position of the repeated elements, is there?

Search and SearchAll return position but they seem to be the only ones.  

Example:

a:=[[x+y+z],[2*x+y+z],[x-y+z],[2*x+y+z]];

and the expected output would be

pos:=[[1],[2,4],[3]];

Many thanks

Ed

 

Hello

I wonder if there is a function to retrieve only the monomials from a multivariable polynomial in x, y and z. Below is one such polynomail.

 

theta[2]*x3*x0-theta[8]*x2*x1*x0-theta[2]*x2*x1-theta[6]*theta[2]*x2*x0^2-theta[4]*theta[2]*x2*x0-theta[2]*theta[7]*theta[10]*x1*x0^3+theta[8]*theta[2]*theta[9]*x1*x0^2-theta[2]*theta[5]*theta[10]*x1*x0^2-theta[2]^2*theta[3]*theta[10]*x0^3+theta[6]*theta[2]^2*theta[9]*x0^3+theta[4]*theta[2]^2*theta[9]*x0^2

and the result

[x3*x0,x2*x1*x0,x2*x0^2,x2*x0,x1*x0^3,x1*x0^2,x0^3,x0^2]

Many thanks

 

Ed

 

Hello

It has been years since I last used maple so I apologize if my question makes no sense and my code is outdated (and wrong!).   

I need to write a function (proc) that uses a functional operator inside.  Something like

test:=proc()

local f,vars, func, aux, res;

f:=arg[1]; # a list

vars:=arg[2]: # a list

aux:=op(vars):

func:=aux -> f:  # a function from () to []

res:=func(op(func(aux))):

return(res):

end:

 

This is the basic idea of the proc.  If f:=[y, y*z-x, -15*x*y-x*z-x] and vars:=[x,y,z], the function of a function does not return as it supposes to.  Please tell me what I am doing wrong and how to improve and update the code.

 

many thanks

 

Ed

 

 

 

Hello

It has been years since I last run one of my packages (not mine actually) and consequently maple.  The package was written in Maple V and run on Maple V5.  I have used updtscr to convert the old code and not many messages came out.   The updated code does not run unfortunately.  One of the problems is the following command:

linalg[dotprod](f,map((a,b) -> diff(b,a),vars,h));

Although linalg is deprecated, that does not seem to be the problem.   Suppose h, f (vector) and vars are:

The output is:

How to avoid the conjugate? Is there a simpler way to do that?

Many thanks for your patience and help.

Regards

 

Ed

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