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hello, I put in the code:

> with(plots), with(ColorTools), with(LinearAlgebra), with(RandomTools), with(ExcelTools);
> A := `<|>`(`<,>`(1, 2, 0, 2, 3, 4, 3, 4, 7, 9, 5, 3, 4, 6, 7, 8, 3), `<,>`(0, 4, 7, 2, 2, 2, 4, 5, 6.5, 7, 5, 3, 2, 5, 9, 0, 1), `<,>`(1, 5, 2, 0, 4, 1, 2, 3, 4.3, 7, 8, 5, 3, 2, 9, 6, 4)); J := convert(Import("testB1.xlsx", "Cartesian", "E2:G18"), matrix);
Error, (in convert/matrix) expecting array, rtable or list
> B := matrix([[1], [.2], [.1], [.8], [.5], [.6], [.8], [.764], [.234], [0.4e-1], [.89], [.36], [.687], [.627], [.689], [.328], [.139]]); H := convert(Import("test.xlsx", "Cartesian", "D2:D18"), matrix);
Error, (in convert/matrix) expecting array, rtable or list
> C := [seq(Color([H[i, 1], 0, 0]), i = 1 .. RowDimension(A))];

 

And i get the error message everytime I try import m data list and I dont understand why. Any help would be appreciated. Thank you

 

Jennifer

I've been using a maple package (written by another author) on earlier versions of Maple.  Recently I have been trying to rewrite it so it's a bit more Maple 16+ friendly (since I've read that Maple is not forward-compatible). However, I have been experiencing similar strange behavior in both the original and my current version: 

After saving the module to my personal library, I load with(MyPackage). Most functions work fine (all but a handful out of dozens).  However, some functions won't be recognized (e.g., Coproduct(...) will return itself Coproduct(...)).  

HOWEVER, when I execute the code in the module in its own Maple worksheet, all functions are recognized and work perfectly.  I look at the difference in the code between the functions that work upon loading the package (using with(MyPackage) command in a separate sheet) and those that don't, and there is no difference.

I'm assuming I'll just have to cut and paste the hundreds of lines of code for my package into each sheet I'd like to use it in, since I haven't been able to find others experience this problem in the knowledge base.  I'm hoping someone will be able to help out, however.

Well, I'm having issues getting this expression to simplify.  I have a bunch of polynomial results I store in an array, and the simplify command isn't cancelling obvious terms which should cancel out.

June_18.mw

Curiously, it will simplify if I use the command by selecting it from the drop down menu when I select the expression (see lines (7) vs. (8))

I am writing a big numerical code in maple. I need to write the results in each step in a file. I mean in the first step of loop it writes the results in the first line of a text file, in the second step writes in the second line and to the end. when I use writedata command, it needs to write a complete array or matrix and it is not what i need. In  other words I want to save data for each steps of iteration during the calculation and when it goes to ther next step it writes the result in the next line.

Can you help me to perform it?

Thanks

Hey everyone,

New here but I'm a bit stuck. Ive looked around in list tools as well as tried but I havent had any luck.

Suppose I have a list defined as FirstList:=[A,B,C,D,E,F]. Now I want to create (and label) all possible
lists from FirstList which contain 4 elements which dont have an element repeated within the same list
In this example, there are 15 lists in total i.e.

Sublist[1]:=[A,B,C,D]:
Sublist[2]:=[A,B,C,E]:
Sublist[3]:=[A,B,C,F]:
Sublist[4]:=[A,C,D,E]:

..etc

Is there a simple way to do this???

Any help is appreciated!

Is there away to quickly execute a specific section within Maple? I know that I can execute a selection, but that sometimes requires me to select several lines of Maple code and can be tedious and tiresome.

Hello everybody,

I am trying to solve a partial differential equation (wave equation) with initial conditions that contain derivative and x-varying values

My equation
Uxx – Utt = 0 (hiperbólica) where xx and tt denote second partial derivatives with respect to x and t
0 <= x <= 10; t > 0;
u(0,t) = u(10,t) = 0;
Ut(x,0) = 0;
u(x,0)=
x for 0 <= x < 5
10-x for 5 <= x <= 10

I ve defined my equation as follow
> PDE := diff(u(x,t),x,x)=diff(u(x,t),t,t);

I m first trying without the x-varying initial condition.

> IBC := {u(0,t)=0,u(10,t)=0,u(x,0)=10-x,diff(u(x,0), t) = 0};
Returns the ugly

And that gives error when trying to solve
> pds := pdsolve(PDE,IBC,numeric);
Error, (in pdsolve/numeric/process_IBCs) initial/boundary condition does not contain the dependent variables of the PDE: 0 = 0

Another try with
> IBC := {u(0,t)=0,u(10,t)=0,u(x,0)=10-x,diff(u(x,t=0), t) = 0};

Looks like more promissing but returns (in a solving attempt)
> pds := pdsolve(PDE,IBC,numeric);
Error, (in pdsolve/numeric/process_IBCs) initial/boundary condition does not contain the dependent variables of the PDE: 0 = 0


Regarding the x varying initial condition, I ve tried the `assuming` keyword in various attempts but without success.

Anybody could help on the matter?


Thanks in advance for anytip.
Have a good day
Nicolas

Hallo,

Is there a fairly straightforward method for obtaining an array of coordinates from an implicit equation? I have an ellipse defined implicitly (by a horrendously involved expression) and can't figure out how to extract a set of coordinates from an implicitplot. I'm reluctant to use seq and fsolve with a fixed stepsize.

Would be grateful for some insight!

Thanks.

Weirp

I wish to  plot 2D animate for the soltion of this equation here is the code

restart;
with(PDEtools):
with(ArrayTools):
with(plots):

f:=u->sech(u):
g:=v->sech(v):
h:=1/10:
N:=20:
M:=20:
V:=x->x^2:
psi:=Array(0..N/h+1,0..M/h+1):
for i from 0 to N/h do
psi[i,0]:=evalf(f(i*h)):
od:
for j from 0 to M/h do
psi[0,j]:=evalf(g(j*h)):
od:
for i from 1 to N/h do
for j from 1 to M/h do
psi[i,j]:=-psi[i-1, j-1]+(1-(1/8)*h^2*V((1/2)*h*(j-i-1)))*psi[i, j-1]+(1-(1/8)*h^2*V((1/2)*h*(j- i+1)))*psi[i-1,j]:
od:
od:
ls:=[seq([seq([i*h,j*h,psi[i,j]],i=0..N/h)],j=0..M/h)]:

surfdata((ls),axes=boxed,labels=[`u`,`v`,`psi(u,v)`],shading=zhue,style=patchcontour);

Hello,

I am writing a program in C that uses the open maple library. It is not the first time that I use it but now I am facing a strange problem that involves the simplify command: suppose a,x,y are symbols that are not previously used in maple, the following lines

1)  EvalMapleStatement(kv, "simplify((a*x^2-y^2)/(x^2*y^2-1));");

2)  EvalMapleStatement(kv, "simplify((2*x^2-y^2)/(x^2*y^2-1));");

only differ by the fact that the parameter a is replaced by 2 in the second line. But they return the following output:

1) (a*x^2-y^2)/(x^2*y^2-1)

that is correct, nothing to simplify..

2) Error, (in gcd/LinZip) input must be polynomials over the integers

I must be doing something wrong but I am getting nowhere...

Thanks...

 

P.S. This is the complete listing 

 

#include <stdio.h>

#include <stdlib.h>

 

#include "maplec.h"

 

static void M_DECL textCallBack( void *data, int tag, char *output )

{

    printf("%s\n",output);

}

 

int main( int argc, char *argv[] )

{

    char err[2048];  /* command input and error string buffers */

    MKernelVector kv;  /* Maple kernel handle */

    MCallBackVectorDesc cb = {  textCallBack,

                                0,   /* errorCallBack not used */

                                0,   /* statusCallBack not used */

                                0,   /* readLineCallBack not used */

                                0,   /* redirectCallBack not used */

                                0,   /* streamCallBack not used */

                                0,   /* queryInterrupt not used */

                                0    /* callBackCallBack not used */

                            };

    ALGEB r, l;  /* Maple data-structures */

        char *myargv[]={"maple"};

        int myargc=1;

 

    if( (kv=StartMaple(myargc,myargv,&cb,NULL,NULL,err)) == NULL ) {

        printf("Fatal error, %s\n",err);

        return( 1 );

    }

 

EvalMapleStatement(kv, "simplify((a*x^2-y^2)/(x^2*y^2-1));");

 

EvalMapleStatement(kv, "simplify((2*x^2-y^2)/(x^2*y^2-1));");

 

    StopMaple(kv);

 

    return( 0 );

}

 

compiled with

gcc prova.c -I /Library/Frameworks/Maple.framework/Versions/Current/extern/include/ -L /Library/Frameworks/Maple.framework/Versions/Current/bin.APPLE_UNIVERSAL_OSX/ -l maplec

Hello,

 

  I have a question. Consider

 

fsolve(x^2+3*x+1=3, x);

 

  I want to save the two roots into two variables. What kind of commend shall I use? 

 

P.S. My further aim comes from solving an equation without analytical solution. Therefore I cannot plug in the solution formula. 

 

 

Who knows: is there a maple command for two matrix multiplication element by element without summing?

 

I'm calculating the geodesics to a parametrized system in R3. When trying to solve the geodesic equations for a surface of revolution, I'm getting a strange error. The goal is to write the code for any parametrized surface, not just revolution (hence I didn't use the short cut for surfaces of revolution).

For the code, I find the first fundamental for, then the geodesics, then turn the christoffel symbols into a time-variant array. (Gamma for the position of (u,v) in the uv-plane, and C as the array so I can take derivatives with respect to time.)

The code for creating the Christoffel Symbols and the parametrization of the paraboloid:

restart; with(LinearAlgebra):
V := (u, v) -> <v*cos(u), v*sin(u), v^2+1>;

Christoff := proc (X)
local x1, x2, M, N, i, j, k, s, E, F, G, g, Q, Delta, Prelim, cyclicPrelim;
global Gamma, C; #GAMMA
x1 := (u, v) -> <diff(X[1], u), diff(X[2], u), diff(X[3], u)>;
x2 := (u, v)-> <(diff(X[1], v), diff(X[2], v), diff(X[3], v))>;
E :=  (u, v) -> DotProduct(x1(u, v), x1(u, v), conjugate = false);
F := (u, v) -> DotProduct(x1(u, v), x2(u, v), conjugate = false);
G := (u, v) -> DotProduct(x2(u, v), x2(u, v), conjugate = false);
simplify([E(u, v), F(u, v), G(u, v)]);
M := (u, v) -> <E(u, v), F(u, v); F(u, v), G(u, v)>;
simplify(M(u,v));
printlevel := 3;
Delta := simplify(Determinant(M(u, v)));
N := (1/Delta)*<G(u, v), -F(u, v); -F(u, v), E(u, v)>;
Q[1] := simplify(map(diff, M(u, v), u));
Q[2] := simplify(map(diff, M(u, v), v));
for i to 2 do for j to 2 do for k to 2 do
Prelim[i, j, k] := Q[k][i, j];
simplify(Prelim[i, j, k] ); end do end do end do;
#(OPTIONAL PRINTOUT) print(Prelim);
for i to 2 do for j to 2 do for k to 2 do
cyclicPrelim[i, j, k] := Prelim[i, j, k]+Prelim[j, k, i]-Prelim[k, i, j] ;
end do end do end do;
#(OPTIONAL PRINTOUT)  print(cyclicPrelim);
for i to 2 do for j to 2 do for k to 2 do
Gamma[i, j, k] := simplify((1/2)*add(N[i, s]*cyclicPrelim[j, s, k], s = 1 .. 2));
end do end do end do;
# for k from 1 to 2 do
#print(`GAMMA[i,j,k] =` Matrix([[ `%a` , `%a` ],[ `%a` , `%a` ]])` \n`, Gamma[1,1,k], [Gamma[1,2,k], Gamma[2,1,k], Gamma[2,2,k]);
# end do;
#printf('GAMMA[%a,%a,%a] = %a \n', i,j,k, Gamma[i,j,k]);

print([Gamma[1,1,1], Gamma[1,2,1], Gamma[2,1,1], Gamma[2,2,1], Gamma[1,1,2], Gamma[1,2,2], Gamma[2,1,2], Gamma[2,2,2]]);

for i from 1 to 2 do
for j from 1 to 2 do
for k from 1 to 2 do
C[i,j,k]:= apply(Gamma[i,j,k],t);
end do end do end do;
C:=Array(1..2,1..2,1..2,[ [ [ apply(Gamma[1,1,1],t), apply(Gamma[1,2,1],t) ], [ apply(Gamma[1,1,2],t), apply(Gamma[1,2,2],t) ] ], [ [ apply(Gamma[2,1,1],t), apply(Gamma[2,2,1],t) ],  [ apply(Gamma[2,1,2],t), apply(Gamma[2,2,2],t) ] ] ]);
print(C);

end proc;

 

The differential equation solver:

inits:=[u(0)=1, D(u(t))(0)=1,v(0) = 1, D(v(t))(0)=1];

sys1:= [D[1$2](u(t))+C[1,1,1]*(D(u(t)))^(2)+2*C[1,1,2]*(D(u(t)))*(D(v(t)))+C[1,2,2]*(D(v(t)))^2=0, D[1$2](v(t))+C[2,1,1]*(D(u(t)))^(2)+2*C[2,1,2]*(D(u(t))*D(v(t)))^(2)+C[2,2,2]*(D(v(t)))^2=0];

L:=dsolve({sys1} union {inits});

 

The error message that comes up is:

"Error, (in unknown) invalid input: op expects 1 or 2 arguments, but received 0"

 

 

Any help would be greatly appreciated.

Hy guys,

I'm starting in Maple and I have a problem, my Maple 16 does not calculate a simple trigonometric function.

When I do:

>cos(pi);

The maple return:

cos(π)

 

 

Thanks a lot!

I have Maple 16 for Windows 64-bit. How to get a printable Maple 16 Quick Reference Card? Also, how to save the Maple 16 Quick Reference Card as a separate file? (When I try to copy the Card I get en error message "selection too large").

 

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