In graph theory, the crossing number cr(G) of a graph G is the lowest number of edge crossings of a plane drawing of the graph G. I'd like to use maple to compute crossing number of some graphs (any graphs is ok,  for example： cr(K5)=1 ). Someone can help me ? thanks. 

I know the problem of computing the crossing number is NP, but I guess we have some good  ways to compute in some small graphs.

Hello,

Since I installed Maple 2019 in my new iMac with Catalina, I can't make it work properly.

1. Once open, it's impossible to shut it down. I always have to force its exit.

2. The context panel doesn't seem to work properly. It never shows the actions that it sould do.

3. It doesn't flow as the old Maple I use to have in my old iMac.

I've been looking for this issue both in this forum and in the whole internet, as well as sending messages to technical support, and still can't find any answers. If someone knows something, plese let me know.

Kind regards,

Fermat66 

I want to factor large numbers, for this purpose I want to utilize multi cores on my computer.

Anyone who can help me in solving this problem?

I am utilizing Lenovo Thinkpad T440s with specifications core i7-4600 CPU @ 2.19 GHz.

In addition I would like to ask if anyone can help me in integrating GPU's with Maplesoft 2019 for factorization.

I am having a cluster of 64 GPU's i.e. AMD RX-460.

Any help in this regard will be appreciated.

Hello people in Mapleprimes,

A long time has passed since I came here before.
I have forgotten a lot of what I remembered about maple.

I want to incert gamma from e_nsp1 and (1-gamma) from e_nsp2 into set_3, so deleting gamma and (1-gamma) from set_3.
How can I do this?

Thank you in advance.

Take care.

question_1.mw

taro 
 

I am using a maple workbook to develop, test, and install a package I am developing.  Several days ago, I noticed that the workbook was not updating the package to reflect the most recent versions of my source code (.mpl). I initially assumed the problem caused by some unintentional change I made to the file, but in the end I found there is a general problem with the URIs in the maple workbook. Everything worked in 2019.1 and I hadn't made any changes after I updated to 2019.2.1.

To confirm the problem, I created a new directory(in fully updated Windows 10 ) and copied my source file into the directory. Then I created a worksheet in maple and saved it into the directory as xx.mw. Using the Navigator panel I then saved the worksheet as a workbook creating xx.maple in the directory.  I then tried to attach the mpl file to the workbook.  In the Navigator menu, the item "attach a file" is unavailable( greyed out).  This is also the case in any of the other earlier workbooks I have created.  I have confirmed the problem is not affecting worksheets because I was able to read my mpl file into a worksheet and load the module using a with(modulename) command.

Please advise.

Can anyone help me with the question? Keep getting the error. I don't know what is going on. Thank you in advance.

QUESTION_6.docx
 

Download Question_6_maple.mw

Hello all

I need to calculate the distance L in a curvefitting. The calculation has been made in MathCAD and I need to copy it in Maple, but I cant seem to make it solve.

Here are the two pictures of my problem:

In MathCAD:

In Maple:

Here is the copy of Maple:

V[Ed13] := [257.184, 230.4, 184.3, 138.2, 92.2, 46.1, 0];
 = 
    V[Ed13] := [257.184, 230.4, 184.3, 138.2, 92.2, 46.1, 0]

x[12];
 = 
            [-149, 208, 567, 925, 1283, 1642, 2000]

L[1] := x[13];
 = 
         L[1] := [0, 358, 717, 1075, 1433, 1792, 2150]

solve(V[Rdc] = CurveFitting:-ArrayInterpolation(x[12], V[Ed13], L[1]), L[1]);
 = 
Error, invalid input: solve expects its 1st argument, eqs, to be of type {`and`, `not`, `or`, algebraic, relation(algebraic), ({list, set})({`and`, `not`, `or`, algebraic, relation(algebraic)})}, but received 153.25 = [HFloat(246.00524369747902), HFloat(211.1381615598886), HFloat(164.98435754189944), HFloat(118.92625698324022), HFloat(72.93816155988858), HFloat(26.784357541899443), HFloat(-19.315642458100548)]

Find 
L[1];

Answer should be 808
 

Hope someone can help as I honestly have no idea how to do this :-)

I want to calculate the below triple integral numerically. I tried different methods and reduced accuracy but nothing works.

Anyone capable?

Thanks

restart;
Digits := 15;
with(VectorCalculus);
v1 := <0, 0, 1>;
v2 := <sin(theta2), 0, cos(theta2)>;
v3 := <VectorCalculus:-`*`(sin(theta3), cos(phi3)), VectorCalculus:-`*`(sin(theta3), sin(phi3)), cos(theta3)>;
v1v2 := CrossProduct(v1, v2);
v2v3 := CrossProduct(v3, v2);
DotProduct(v1v2, v2v3);
(simplify(VectorCalculus:-`*`(%, VectorCalculus:-`*`(Norm(v1v2), Norm(v2v3))^VectorCalculus:-`-`(1))) assuming (0 < theta2, theta2 < Pi, 0 < theta3, theta3 < Pi));
evalf(VectorCalculus:-`*`(Int(VectorCalculus:-`*`(arccos(%), sin(theta3)), [theta2 = 0 .. Pi, theta3 = 0 .. Pi, phi3 = 0 .. VectorCalculus:-`*`(2, Pi)], epsilon = 0.001, method = _d01akc), VectorCalculus:-`*`(VectorCalculus:-`*`(VectorCalculus:-`*`(VectorCalculus:-`*`(VectorCalculus:-`*`(2, Pi), 2), Pi), 4), Pi)^VectorCalculus:-`-`(1)));

Hey there

I have noticed that after some time, Maple freezes and says in the bottom left corner that it is "evaluting" when I  copy something. This is becoming unbearable, as it makes every assignment take a lot longer. Why is this happening, and how can I prevent it?

Hi

I need your help with this problem. The date protocol here in the antipodes is day/month/year.

I get this error...Maybe there is an alternative.

does_not_evaluate.mw

Hello, I have a question about converting an output of a expression into another.

solve({-1 < x, 0 < 2*x/(x^2 - 1), x < 1}, {x})

This is my expression which evaluates into: . Which is correct but I would like it to be a classic range, more precisely (-1,0).

Is there a command to do that?

Thanks,

David.

I compared the numerical value of an integral expression in Gradshteyn and Rhyzhik (8.431.5) for the BesselI(v,z) function to the BesselI(v,z) function in Maple 2019.2 and got different answers.  The GR expression is the difference of two integrals and it looks like Maple only evaluates the first integral, which is correct only if the order v is an integer.  Please see the attached.

BesselI.mw

Hello,

I am trying to pass the graphics to .txt format so that I can plot them in Origin (OriginLab).

npontos := 10;
dt := 0.02;
fd := fopen("out.txt", WRITE);
for i from 0 to npontos do
    t[i] := i*dt;
    PA[i] := x[i](t);
    printf("%e %e\n", t[i], PA[i]);
    fprintf(fd, "%e %e\n", t[i], PA[i]);
end do;
0.000000e+00 

Error, (in fprintf) number expected for floating point format
fclose(fd);
npontos := 10;
dt := 0.02;
fd := fopen("out.txt", WRITE);
for i from 0 to npontos do
    t[i] := i*dt;
    PB[i] := x[i + n](t);
    printf("%e %e\n", t[i], PB[i]);
    fprintf(fd, "%e %e\n", t[i], PB[i]);
end do;
fclose(fd);
0.000000e+00 

Error, (in fprintf) number expected for floating point format
npontos := 10;
dt := 0.02;
fd := fopen("out.txt", WRITE);
for i from 0 to npontos do
    t[i] := i*dt;
    qA[i] := x[i + 2*n](t);
    printf("%e %e\n", t[i], qA[i]);
    fprintf(fd, "%e %e\n", t[i], qA[i]);
end do;
fclose(fd);
0.000000e+00 

Error, (in fprintf) number expected for floating point format
npontos := 10;
dt := 0.02;
fd := fopen("out.txt", WRITE);
for i from 0 to npontos do
    t[i] := i*dt;
    qB[i] := x[i + 3*n](t);
    printf("%e %e\n", t[i], qB[i]);
    fprintf(fd, "%e %e\n", t[i], qB[i]);
end do;
fclose(fd);
0.000000e+00 

Error, (in fprintf) number expected for floating point format
npontos := 10;
dt := 0.02;
fd := fopen("out.txt", WRITE);
for i from 0 to npontos do
    t[i] := i*dt;
    Tg[i] := x[i + 4*n](t);
    printf("%e %e\n", t[i], Tg[i]);
    fprintf(fd, "%e %e\n", t[i], Tg[i]);
end do;
fclose(fd);
0.000000e+00 

Error, (in fprintf) number expected for floating point format
npontos := 10;
dt := 0.02;
fd := fopen("out.txt", WRITE);
for i from 0 to npontos do
    t[i] := i*dt;
    Ts[i] := x[i + 5*n](t);
    printf("%e %e\n", t[i], Ts[i]);
    fprintf(fd, "%e %e\n", t[i], Ts[i]);
end do;
fclose(fd);
0.000000e+00 

Error, (in fprintf) number expected for floating point format

trabalho_final_2019.mw

I would like to know how to create a group with some elements (numbers) {1,2,4,...} with a defined operation on it like X_42 (modular  multiplication by 42).

What is the command to yield the expansion of Z^N in terms of x and y.

Z complex = x+iy,

N integer >1

e.g. Z^2 = x^2 - y^2 + 2.i.x.y