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I am considering to write a wrapper for plot and related commands (could redefine the commands or introduce a new name) which facilitates export of Maple plots to postscript. The command should interpret some of the options and remove them from the options sequence before submitting the remaining ones to the original plot().
E.g. it should recognize a title="TITLE" parameter and process TITLE (e.g. write it to a specific file). Similarly I would want to be able to pass additional parameters, e.g. filename="FILE" in order to specify how the output file name should be set. Is this a sensible approach. How can I realize this detailed option 'parsing' in Maple?

Hi all,
I am writing a procedure that I would like to have several outputs. The code is as follows:

Initialize := proc (p, theta, PiV, PiU, n, m)

J := CompJ(PiU, m);

for i to n do

if member(i, V) then

Ai[i] := CompAi(PiU, PiV, i, n, J)

end if

end do

end proc

The function calls other functions previously defined that are not important here. Basically I would like to return the set J and the list Ai, but I am not sure on how to do it. 

Once the procedure returns these elements, I would like to assign them to some variables. I am not sure on how this can be done when a function returns more than one thing.

Thanks in advance for the help

Sorry if this has been already posted.


When print() is invoked from a proc into a module, non-English characters are not properly displayed with Maple 18.

It works ok if it is invoked from within the workbook.


print("Están en perspectiva")

Put this sentence in a proc into a module and the character "á" wont be displayed

Output: "Est�n en perspectiva"

Any hint about how to treat this issue?

Thank you very much.

César Lozada 




I want to display the matrix M, I used return M, in this procedure, but no matrix M displayed.

local M,i,p;
for i from 1 to 2*N+1 do
for  p from 1  to 2*N+1  do
   if p=1 then M[p,i]:=-2;
    elif  p=2*N+1  then M[p,i]:=-3;
end if; end do; end do;
return M;
end proc;


Many thinks

firstly apologies in advance for stuff in this question such as "triangle symbol",  my computer is pretty old. 

ok so i was confused a bit here, what i'm trying to do is write a maple procedure that computes Af for a given f contained in V . except we only need to correct the bug in the script below. This script demonstrates such a procedure in the case that omega is a square. The domain is given here as the negative set of a function F contained in V .  I have left in notes where/what i think we need to do but i dunno how to...

N:=10 ; # Global Var
Average := proc(F, f0) local f, i, j;
f := f0; # !!!!!!!!!!!!!! something is bad here...
for i to N do for j to N do
if F(i, j) < 0 then
f[i, j] := (f0[i - 1, j] + f0[i + 1, j] + f0[i, j + 1] + f0[i, j - 1])/4 ;
end if;
end do;end do;
return f;
end proc;
f0:=Matrix(N,F); # just to have something to test the procedure
Average(F,f0); # does not return the expected average, modifies f0


the necessary information we were given to produce this so far was..

Let N be a positive integer and [N] = {i contained in N | 1<= i <=N }  Let "Omega" C {(i,j) contained in [N] x [N] | 2<=i,j<=N-1} be a subset. Let V = R^([N]x[N]) be the vector space of real valued functions [N]x[N] -> R
and A, "triangle symbol":V->V (average) and "triangle symbole" (Laplacian) be the linear maps such that
[Af](i; j) = f(i; j)      if (i; j) not contained in "Omega"   OR

                             [f(i, j + 1) + f(i, j - 1) + f(i + 1, j) + f(i - 1, j)]/4 if (i,j) is contained in "Omega"

["traingle symbol"f](i,j) =  0 if (i,j) isnt contained in "Omega"   OR

                            ( f(i,j) - [f(i, j + 1) + f(i, j - 1) + f(i + 1, j) + f(i - 1, j)]/4 )    if (i,j) is contained in "Omega"

 Please and thank you for any help in advance <3



Dear the specialst in programmation, please I need to put a conditon if in this procedure with this form: Can you correct me this code please. Thank you.

local bb,
for i= from 1 to N do


if bb[i]<=2 then y:=3*x[i] else y::=x[i]^2end if ;

end do:

end proc



Dear all;

Please I need your help to find the error in my code.

I want to solve an ode, with condition on step size.

ode := diff(y(x), x) = 2*x+y(x);

analyticsol := rhs(dsolve({ode, y(0) = 1}));
RKadaptivestepsize := proc (f, a, b, epsilon, N)
local x, y, n, h,k,z,R,p;
h := evalf(b-a)/N; ## we begin with this setpsize
x[0] := a; y[0] := 1; ## Initialisation
for n from 0 to N-1 do  ##loop
x[n+1] := a+(n+1)*h;  ## noeuds
k[1] := f(x[n], y[n]);
k[2] := f(x[n]+h, y[n]+h*k[1]);
k[3] := f(x[n]+h/2, y[n]+h/4*(k[1]+k[2]));
z[n+1] := z[n]+(h/2)*(k[1]+k[2]);## 2-stage runge Kutta.
y[n+1] := y[n]+(h/6)*(k[1]+k[2]+4*k[3]);
R:=abs(y[n+1]-z[n+1]); ## local erreur
if R=<=epsilon    then
   x[n] := x[n+1]+h;


end if
 end do;
[seq([x[n], y[n]], n = 0 .. N)];
[seq([x[n], z[n]], n = 0 .. N)];
end proc:

RKadaptivestepsize((x,y)->2*x-y,0,1, epsilon,20)



so we have to Write a maple function with -> that takes an integer N and a boolean function

F: {(i,j) l 0<= i,j<= N} -> {true,false} 

and returns a list containing all [i,j] such that F(i,j). A procedure that does this
would be

proc(N,F) local i, j, RV;
for i from 1 to N do for j from 1 to N do
if F(i,j) then RV:=RV,[i,j] ; end if ;
end do ; end do ;
return RV ;
end proc ;

The problem is to do this inline, i.e. you have to write
(i,j)-> ...


please help...

I am trying some data analysis on an Excel worksheet using Maple. I have the following procedure but I don't know how to make it work for a specific subset of cells (this is a psychological studiy, so I want to have all my scores for each subject, located on the rows, and variable, located on a subset of columns). Example: I want to get an array of all the average scores in a rectangle of cells which goes horizontallyfrom A to AB, and vertically from row 1 to 15. Hope you can help me out! Cheers!

MediaRighe := proc (M) local i, j, r, c, S, N; r := LinearAlgebra:-RowDimension(M); c := LinearAlgebra:-ColumnDimension(M); S := Array(1 .. r); for i to r do S[i] := 0; N := 0; for j to c do if M(i, j) <> "-" then S[j] := S[j]+M(i, j); N := N+1 end if end do; S[i] := S[i]/N end do; return S end proc

I also have this for the columns (same thing, basically):

MediaColonne := proc (M) local i, j, r, c, S, N; r := LinearAlgebra:-RowDimension(M); c := LinearAlgebra:-ColumnDimension(M); S := Array(1 .. c); for j to c do S[j] := 0; N := 0; for i to r do if M(i, j) <> "-" then S[j] := S[j]+M(i, j); N := N+1 end if end do; S[j] := S[j]/N end do; return S end proc

Thanks everybody!

I am a new user of Maple. Could anyone help me to know how to call a Maple function/procedure from a Matlab program with a simple example? And conversely, how to call a Matlab function from Maple.

Hi everyone

I am currently trying to make my own simple package including a few procedures. So far I have been able to write some "code" that actually works when I open the document and hit "enter". I would, however, like to save the package so it can be accessed during any Maple session using the command "with". I have unsuccesfully tried to comprehend the Maple help pages regarding this question but I definitely don't want to mess things up.

This is what I have written:

mat := module ()
description "useful procedures for mathematics, physics and chemistry";
export AtomicWeight;
option package;

   AtomicWeight := proc (x) description "returns the average atomic mass of the naturally ocurring element";
   Units:-AddSystem(NewSystem, Units:-GetSystem(SI), u);
   return evalf(ScientificConstants:-Element(x, atomicweight, system = NewSystem, units))
   end proc

end module;

What should I do to save it correctly?

Thank in advance,





Please help me, here my problem:


Parsing a string works correctely like this:

ABC := 3443;

print("ABC = ", eval(parse(cat("A", "B", "C"))));



But using PROCEDURE it doesn't work:

myParse := proc ()

     local PEA;

      PEA := 4334;

      print("PEA = ", eval(parse(cat("P", "E", "A"))))

end proc;


                        "PEA = ", PEA


I suppose to have "PEA = ", 4334

Following previous question at

and also

I wrote the following code






eq2:=diff(T(eta),eta,eta)+1/(k(eta)/k1[w])*(2/(1-zet^2)*rho(eta)*c(eta)*u(eta)/(p2*10000)+( (a[k1]+2*b[k1]*phi(eta))/(1+a[k1]*phi1[w]+b[k1]*phi1[w]^2)*diff(phi(eta),eta)-k(eta)/k1[w]/(1-eta)*diff(T(eta),eta) )):
rho:=unapply(  phi(eta)*rhop+(1-phi(eta))*rhobf ,eta):
c:=unapply(  (phi(eta)*rhop*cp+(1-phi(eta))*rhobf*cbf )/rho(eta) ,eta):



p:=proc(pp2) global res,F0,F1,F2:
if not type([pp2],list(numeric)) then return 'procname(_passed)' end if:
res := dsolve({eq1=0,subs(p2=pp2,eq2)=0,eq3=0,u(0)=0,u(1-zet)=0,phi(0)=phi0,T(0)=0,D(T)(0)=1}, numeric,output=listprocedure):
evalf(2/(1-zet^2)*Int((1-eta)*(F1(eta)*rhop+(1-F1(eta))*rhobf)*( F1(eta)*rhop*cp+(1-F1(eta))*rhobf*cbf )/(F1(eta)*rhop+(1-F1(eta))*rhobf)*F0(eta),eta=0..1-zet))-pp2*10000:
end proc:




phb:=evalf(2/(1-zet^2)*(Int((1-eta)*F0(eta)*F1(eta),eta=0..1-zet))) / evalf(2/(1-zet^2)*(Int((1-eta)*F0(eta),eta=0..1-zet))) :



as you can see at the second line of the code, the value of phi0:=0.00789. however, I want to modify the code in a way that phi0 is calculated with the following addition constraint

evalf(2/(1-zet^2)*(Int((1-eta)*F0(eta)*F1(eta),eta=0..1-zet))) / evalf(2/(1-zet^2)*(Int((1-eta)*F0(eta),eta=0..1-zet)))-0.02=0

I would be most grateful if you could help me in this problem.

Thanks for your attention in advance


Hi, I am currently creating a procedure so that i can input two matrices and a vector and multiply them together in different patterns, I want the result to be either one of the vectors {4,0,0,0} or {0,4,0,0} or {0,0,4,0} or {0,0,0,4}, I am trying to create an if loop that says is one of the S's is equal to one of these print ("Synchronising"), I have decalred these vectors inside the procedure and all the S's but my if statement is still not working. I think S needs to be decalred more clearly inside but i'm unsure what to do, any help would be much appreciaited! Here is my procedure:


local s, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14, e, f, g, h;
if (s7 = e)then
elif (s7 = g) then
print ("Synchronising")
elif (s7 = h) then
print ("Synchronising")
elif (s7 = g) then
print("Not Synchronising");
end if;

return s, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12, s13, s14;
end proc:



Hi there!

I want to improve the way I code up my procedures. For instance I want to code them safe in the sense that they only accept the arguments when they have the correct type.

I know that in principle this is done with the double-colon operator in the following way:



(Q1)Now, given that my argument is of a type such as set, list, Array, etc.:

(a) How would I specify the allowed types of the elements of that list (for all elements, and for specific ones)? And if the element of the list is a list again, how would I specify the type of that's elements? and so forth..

(b) How would I specify the allowed size of the listArray, etc. ?


(Q2) How do I specify the types of more than one output, if my proc returns more than one value?


(Q3) I know that there are special integer types, such as nonnegint, posint, negint. Is there also a way to specify that the ineger (or float) argument has to be greater than some given value, e.g. >2, or that it has to lie between two values, or out of a given set?


Thats all for now. Thanks for your help guys! : )


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