How I can solve a PDE on two regions with matching conditions at the common boundary?  

T1.mw

In Maple 2023 I haven't been able to sign in to the Maple Cloud.
In Maple 2022 there was no problem. In fact in my Maple 2022.2 I'm actually signed in right now.

I need this to get updates to the Physics updates. 
The toolbar in 2023.2 has a grayed out icon saying "Sign in". Nothing happens if I click on it.

PS. I'm also signed in right now to Maple 2021.2. So the problem couldn't be that I cannot be logged in to more than one Maple release.

[Moderator: long pasted output deleted - OP has provided file in reply]

According to the documentation of MmaTranslator:-Mma:-PolynomialReduce, this command yields . However, 

restart;
MmaTranslator:-Mma:-PolynomialReduce(x**2+y**2,{x-y,y+a});
 = 
                       [         2    2]
                       [[0, 0], x  + y ]

In[1]:= PolynomialReduce[x^2+y^2,{x-y,y+a}](*Mathematica*)

Out[1]= {{x + y, -2 a + 2 y}, 2 a^2}

In SymPy and in MuPAD: 

The output of both is the same as that of Mma; only the result given by Maple is inconsistent with Mathematica's. 

The example above is so simple that the desired result can be found simply by hand. Here is a larger example: 
Given two polynomials .txt and .txt, as well as a list of polynomials .txt, I would like to evaluate 

# Suppose that one has downloaded these three files. 
poly1, poly2 := fscanf("poly1.txt", "%a")[], fscanf("poly2.txt", "%a")[]:
pList := MmaTranslator:-Mma:-ReadList("pList.txt"):
MmaTranslator:-Mma:-PolynomialReduce((a - poly1)*(a - poly2), pList);

 But its result is just “[[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], …]”, while when a＝0 it should be “[[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 1, 0, 0, 0, 1, 2, 1, 0, 2, 2, 3, 1, 1, 1, 2, 1, 0, 0, 0, 1, 1, 2, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0], 0]”.
So why does  return a distinct value?

Can MapleSim simulate a situation where a cable passes through a hole in an object, where the cable is constrained by the hole and the object also experiences forces from the cable because of the hole?

How would I solve for the product of two terms ( s*V or s^2*V). This is a simple example but I would be applying this on much higher order equations.

     V = Vx/(a*s^2 + b*s + c)

How do i retrieve the expression fra a "Fit" command so that i can use the expression for later calculations.

As you can see from the picture below, i use the "Fit" command to find an expression based on the values specified in X and Y. From there i would like to use the expression to find points on the line and to automate the proces. I can succesfully retrieve the expression by using the reference label, but is there another way to retrieve the expression so that i can avoid having to display the expression after evaluating?

I guess the question can be rephrased to: How do i retrieve the same information as the label reference does, but with a command and without using a label reference?

Hello, 

What would be the procedure to find the eigenvalues for a coupled harmonic oscillators characterized by eigenvalue E1 and E2? Are they treated as parameters in the numerical solution of the system of ode?

thanks in advance 

Hello,

I am having problems using RowEchelonTransform from the LinearAlgebra[Modular] package. According to the documentation, it returns a triple

Q,rp,d:=LinearAlgebra[Modular][RowEchelonTransform](p, M, false, false, false, false):

where Q and rp are vectors of length r=rank(M). In more detail, rp=[c1,...,cr] lists the (linearly independent) pivot columns, and Q is a list of transpositions that can be used to construct the pivot rows (denoted by the matrix P in the documentation).

Anyway, these details are not so important. My problem is that Q is not always a list of length r. The example

p:=29:
M:=LinearAlgebra[Modular][Mod](p, [[-1,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,1,-1,-1,-1,-1],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,-1,-1,1,1,1,1],[0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,0,0,0,1],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,0,0,0,-1],[0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0,0,0],[0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,-1,0,0,1,0,0,0,0,0,0,0,0,0],[0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,0,0,0,0],[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0]], integer[]):
Q,rp,d:=LinearAlgebra[Modular][RowEchelonTransform](p, M, false, false, false, false):

is a 16x39 matrix M of full rank r=16. I get the output

Q=[1, 9, 5, 5, 13, 10, 10, 11, 10, 14, 15, 12, 15, 16, 16]
rp=[1, 2, 3, 4, 5, 8, 9, 10, 11, 15, 16, 18, 19, 22, 29, 34]

where rp has 16 elements as expected, but Q has only 15 elements.

Hence there is either a bug in RowEchelonTransform, or the documentation of its output is inaccurate.

I reported this to technical support (the Software Change Request Form on MaplePrimes sadly does not work and shows an error when I tried to submit the filled form).

In the meantime, does anyone know a workaround for this?

With thanks,

Erik

Since (1/h)[f(i+1,t)-f(i,t)]=f(x,t)_{x} as h goes to zero, 'i' is the discrete index along x-axis. How to do it in Maple? How to reduce Eq. (5) into continuous derivatives?

Download limit.mw

Hi:

I am using solve(...,allsolutions)

and Maple is giving me the default "_Z1~" as part of the solution. No problem.

But when I go back and run the same statement again without a restart, it gives me "_Z2~" and my program fails because it is looking to substitute a value for "_Z1".

How do I reset the naming convention without restarting so I can get the same output each time I run the same statement. (BTW: The same thing happens with Veil where it increments the indices of the Veil symbol each time you run the same statement)..

Thank you.

When opening a new Worksheet I am given an option to start a new server. When I close said worksheet the server closes. With no worksheets open I can see "Server 2" is available. If use it to open a new worksheet and the close said worksheet, "Server 2" remains available. Is this normal? Is it actually available or is it just a display feature?

I am really confused by this behavior. Should the solution be different when calling dsolve(ode) vs. dsolve(ode,[x(t),y(t)]) where here ode is list of two coupled first order ode's?

Maple shows the solutions in reverse order in one case vs. the other. I do not see why adding [x(t),y(t)] should make x(t) solution now y(t)'s and y(t) solution now x(t)'s.  Here is an example

Here is worksheet. I just find the out changing very confusing. Should not the same solution for x(t) and y(t) remain the same regardless of adding the second option as list of not? What is the logic behaind this change or order, and how it one to know which is the correct one as they look different.

Download why_solution_changes_nov_27_2023.mw

Is it possi le to ge a transfer function from a bode plot ?

How to plot this equation

 y(x):=

where,

A := Matrix([[1, -1, 1, -1], [1, 1, -1, -1], [-1, 1, 1, -1], [1, 1, 1, 1]]);
B := Matrix([[1], [0], [1], [0]])