Hi every one

Let F=[f1,...,f10] be a  list of homogeneous polynomials with different degrees. I want to create a list of lists s.t. any list satisfies the following conditions:

1. all elements of a list have the same degree.

2. the lists contained in the main list sort increasingly.

For example if F=[x-y, y+z, x^3-xyz+z^3, y^3-xz^2, y^6-x^4y^2, x^5y-z^6+x^2y^2z^2] then 

L=[[x-y, y+z],[x^3-xyz+z^3, y^3-xz^2],[y^6-x^4y^2, x^5y-z^6+x^2y^2z^2]] is the output.

Thanks for your answers.

It would be nice to have a point probe for images ie.pixel location. 

Maple code for solving system of ODE using forward-backward sweep method.

While working a test workbook in Maple 2023 - added a file went away for a while and came back and started adding code to the workbook when I suppose it did an autosave and this error came up 4x in a row. 

Dears,
How can I work with a LogNormal distribution represented by a mean and standard deviation?
I see that is with exp(Normal(mu,sigma)), but I dont sure. Would you please help me with a example using LN(mean=20,standard deviation=5)?
I will use in PDF, CDF and RandomVariable. 

For a table

T := table(sparse = {}, [1 = {a}, 2 = {b}])

T[3] returns {}. 

Is there an equivalent for an rtable?

Download Sparse.mw

Hi, 

I am stuck on how to graphically represent my two G and S shapes. Any suggestions to help me illustrate this concept of a ruled surface?

Thank you

SurfaceMP.mw

I expect that there must exist a Maple proc that does the equivalent of the following but I couldn't find it.  Can it be in the combinat package?

And if there isn't one, can the following be improved?  It seems to be horribly inefficient to me, although efficiency is not a major concern for me right now since I need it only for small values of n.

Download mw.mw

Hi,

I have copied codes from the example of the pendulum to use for a simple case of the motion of a particle in the gravitational field. But when it is time to find v_, I get 0 while in the examples worksheet, it works? I try it in Maple 2022 and 2023 so it is not a question of a version of Maple. It seems that I am missing something. Some help would be appreciated.

Here is my Example_1.mw.

Thank you.

Hi 

I have a question concerning the matrix. Is there any Maple command or function for counting the nonzero elements in any row of a matrix?

Thanks for your help.

Hello

I am running Maple 2023 on a mac M1. When I ask Maple to print a document with 3D figures, only the axes come out. 2D figures come out fine.  If I do the same thing on Maple 2022 on the same machine, there is no problem at all.   

Can any one confirm this problem?

many thanks

When we specify a set (a sequence of objects enclosed in curly braces), Maple removes duplicates, since the elements of the set must be unique, that is, they cannot be repeated. See below for 2 examples. With the first example  {a<=b  and  b>=a}, everything is in order, since they are one and the same. But Maple treats the same equality, written in two ways  {a=b, b=a} , as different objects. It seems to me that this is not very convenient:

restart;
{a<=b, b>=a}; # OK
{a=b, b=a}; # not OK
is((a=b)=(b=a)); # not OK

Hi,

Would  anyone here  be interested in helping me with a genus problem and running the following code and letting me know the genus?  I do not have Maple and have tried other avenues for help without success; the on-line Magma calculator cannot compute it and Mathematica does not have a genus function.  I believe the following is the correct syntax to compute the genus however it may take a while.

with(algcurves);

f:=2*z^6 + z^7/2 - (5*z^11)/4 + 4*z^22 + (29*z^34)/10 - z^40 - (13*z^43)/2 + w^38*(z^2 - z^7/4) + 
 w^49*(-z^9 + z^13/4 + 2*z^14) + w^34*((7*z^14)/3 - (3*z^18)/2) + w^47*(z^10/3 + (7*z^11)/4 + (8*z^21)/5) + 
 w^24*(4*z^8 + (4*z^25)/5 - (3*z^27)/2) + w^9*((-6*z^2)/5 - z^6/2 + (7*z^31)/3) + 
 w^16*((7*z^21)/3 + (4*z^27)/5 + (4*z^32)/3) + w^18*(-6*z^14 - 2*z^31 - z^33) + w^3*(2*z^17 + (7*z^34)/2) + 
 w^16*((-3*z^5)/4 - 2*z^36 + z^39/3) + w^50*(-1/3*z^23 - (7*z^40)/2 + z^42) + w^4*((-3*z^30)/2 + (4*z^38)/3 + (8*z^42)/5) + 
 w^33*(-3*z^4 + (8*z^22)/3 - (8*z^43)/5) + w^16*(-1/4*z^26 - (3*z^41)/4 - z^43) + w^48*((2*z^2)/3 + 6*z^26 + (3*z^43)/5) + 
 w^49*(2*z^18 + z^36 - 2*z^44) + w^10*((-2*z^11)/5 - (3*z^26)/2 + z^45) + w^40*(-1/2*z^20 - z^29 + z^46) + 
 w^36*(-4 + 8*z^13 - (7*z^47)/4) + w^14*((7*z^24)/5 - 6*z^32 - 6*z^49) + w^22*(-2*z^27 - (8*z^50)/3) + 
 w^2*((3*z^10)/5 + (7*z^24)/4 - z^50/4);

genus(f,z,w)

perturb_mag_current_density_2.mw

I am trying to calculate the electric field E induced in a vibrating cantilever of conductive material, oscillating in the field of a permanent magnet.  However, I am having some difficulty getting pdsolve to work the way I want it to.  I'm also not sure if the partial differential eqations I derived from Maxwell's equations are correct, or if the boundary conditions for the electric field in the cantilever are correct.  Currently pdsolve gives me no solutions, which makes me think that either my PDEs or my BCs are not correct.  It may be that I need to try some sort of numerical method as well.  I am assuming that the z component of the electric field is just 0.  My third PDE comes from setting the divergence of the electric field to 0.  My first two PDEs come from the vector laplacian and its relation to the divergence and curl:

Laplacian * E = Div(E) -Curl(Curl(E))

The x and y components of this should be my first and second PDE, respectively.  Note that in this equation the divergence of E is 0, and the curl of E is -dB/dt, where B is the magnetic field.

My boundary conditions are simply that the components of the electric field at the surface of the cantilever is always tangent to the surface.

I have tried various simplifications, such as setting the right hand side of the PDEs to 0, and still I don't get any solution.

My question:  Are my PDEs and BCs sensible?  And if so, what do I need to do with pdsolve to get a proper solution?

Hi everyone,

I am trying to find the roots of a system of 3 multivariate polynomials with 3 variables. I have used

G := Basis(P, tdeg(x6, x7, x8))

from the Groebner package and got a Groebner Basis with 29 elements (the length of output exceeds the limit). I want to find roots in the interval [0,1] with x<y<z. Is there a way to find solutions? Some of the polynomials in the Basis are of order 11 and I can't find a single variable polynomial in the basis. Is there an efficiet way to find such roots? Or should I do someting completely different?

Best

fabs