Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

Are there any restrictions regarding path and filename length in Maple?

I am experiencing problems working with a file on a server, path and file length is 207 characters.

Maple 2022.2

> restart
> expr = x^4-10*x^2+1
> plot(expr)

produces an error message:
com.maplesoft.maplets.ComponentAccessException: not a valid plot structure

plot(expr, x) works Ok.

Tom Dean

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

T1.mw

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)

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 

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]])

As a part of my learning curve, I am trying to play with extending Maple's BernsteinBasis, which has only a limited support right now (BernsteinBasis - Maple Help (maplesoft.com)).

My goal is to implement basis operation on polynomials in Bernstein basis, so that derivatives, integrals and products of polynomials in  BernsteinBasis would be again expressed in BernsteinBasis.

While it looks like it is relatively easy to extend diff procedure, by using `diff/BernsteinBasis`, I didn't find anything similar for the int. Is there something like `int/BernsteinBasis`?

The problem is that when I am trying to implement my own int procedure in a module that  would extend standard int, it seems I need to manually implement logic for (at very least) linearity, so that int(p(x) + q(x), x) would decay into int(p(x), x) + int(q(x), x ) (I probably don't need more complex rewriting rules). So before trying this approach, is there any easy way such as with diff?
 

restart;

read("C:\\Users\\Igor\\Maple\\BernsteinPolynomials.mpl");

_m2141342686560

(1)

# General formula
diff(BernsteinBasis(k, n, a, b, x), x);

n*BernsteinBasis(k-1, n-1, a, b, x)/(b-a)-n*BernsteinBasis(k, n-1, a, b, x)/(b-a)

(2)

# In expressions
diff(2*x*BernsteinBasis(1, 2, 0, 1, x) + BernsteinBasis(2, 2, 0, 1, x), x);

2*BernsteinBasis(1, 2, 0, 1, x)+2*x*(2*BernsteinBasis(0, 1, 0, 1, x)-2*BernsteinBasis(1, 1, 0, 1, x))+2*BernsteinBasis(1, 1, 0, 1, x)

(3)

# Convertion to MatrixPolynomialObject works
p := diff(BernsteinBasis(1, 2, 0, 1, x) + BernsteinBasis(2, 2, 0, 1, x), x);
P := convert(p, MatrixPolynomialObject, x);
P:-Value(a);

p := 2*BernsteinBasis(0, 1, 0, 1, x)

 

P := Record(Value = Default[value], Variable = x, Degree = 1, Coefficient = coe, Dimension = [1, 1], Basis = BernsteinBasis, BasisParameters = [1, 0, 1], IsMonic = mon, OutputOptions = [shape = [], storage = rectangular, order = Fortran_order, fill = 0, attributes = []])

 

Matrix(%id = 36893490288797933188)

(4)

# Now, integrataion
with(BernsteinPolynomials);

[int]

(5)

# Still works
int(x^2, x);

(1/3)*x^3

(6)

# Not implemented but will be added later...
int(BernsteinBasis(1, 2, 0, 1, x), x);

"Will be implemented here..."

 

int(BernsteinBasis(1, 2, 0, 1, x), x)

(7)

# This is the problem: how to implement basis properties such as linearity?
int(2 * BernsteinBasis(1, 2, 0, 1, x), x);

int(2*BernsteinBasis(1, 2, 0, 1, x), x)

(8)

 

 

BernsteinPolynomials := module()
    description "Basic operations in Bernstein basis";
	option package;
	global BernsteinBasis, `diff/BernsteinBasis`;
	export int;

	BernsteinBasis := proc(k, n, a, b, x)
		description "Bernstein basis polynomial";
		if k::numeric then
			if k < 0 then 
				return 0;
			end if
		end if;
		if n::numeric then
			if n < 0 then 
				return 0; 
			end if;
			if k::numeric then
				if k > n then
					return 0;
				end if;
			end if;
		end if;
		'procname'(_passed)
	end proc;

	`diff/BernsteinBasis` := proc()
		description "Derivative of the Bernstein basis polynomial in the Bernstein basis";
		if _npassed = 6 then
			if _passed[-1] = _passed[-2] then
				_passed[2] * BernsteinBasis(_passed[1] - 1, _passed[2] - 1, _passed[3], _passed[4], _passed[5]) / (_passed[4] - _passed[3]) -
				_passed[2] * BernsteinBasis(_passed[1], _passed[2] - 1, _passed[3], _passed[4], _passed[5]) / (_passed[4] - _passed[3]);
			end if;
		end if;
	end proc;
	
	int := proc()
		description "Integral of the Bernstein basis polynomial in the Bernstein basis";
		if type(_passed[1], 'specfunc'(anything, BernsteinBasis)) then
		    print("Will be implemented here...");
		end if;
		:-int(_passed)
	end proc;

end module;

Download bernstein.mw

In my code, without knowing what the expression is, other than it has RootOf, the code called allvalues and got internal error 

Error, (in SolveTools:-Basis) invalid input: igcd received 5/7, which is not valid for its 2nd argument

Is this to be expected depending on the input, or is this some internal problem I need to report?

restart;
expr:=RootOf(R^4*b+R^2*a*_Z+2*_Z^2-exp(RootOf(tanh(1/2*(a^2-8*b)^(1/2)*(4*S-_Z)/a)^2*R^4*a^2-8*tanh(1/2*(a^2-8*b)^(1/2)*(4*S-_Z)/a)^2*R^4*b-R^4*a^2+8*R^4*b-8*exp(_Z))))

allvalues(expr)

Error, (in SolveTools:-Basis) invalid input: igcd received 5/7, which is not valid for its 2nd argument

Maple 2023.2 on windows 10

ps.  Reported to Maplesoft

restart

V := m^4*(1-(varphi/mu)^p);

m^4*(1-(varphi/mu)^p)

(1)

V1 := diff(V, varphi);

-m^4*(varphi/mu)^p*p/varphi

(2)

V2 := diff(V1, varphi);

-m^4*(varphi/mu)^p*p^2/varphi^2+m^4*(varphi/mu)^p*p/varphi^2

(3)

f := Zeta * (varphi^2);

Zeta*varphi^2

(4)

f1 := diff(f, varphi);

2*Zeta*varphi

(5)

f2 := diff(f1, varphi);

2*Zeta

(6)

R:= simplify(((V/3-f1*V1/(3*V))/((1-kappa^2*f)/(12*kappa^2)+f1/V)));

4*kappa^2*m^4*(-3*(varphi/mu)^(2*p)*m^4+(varphi/mu)^(3*p)*m^4+3*(varphi/mu)^p*m^4-m^4-2*Zeta*(varphi/mu)^p*p+2*Zeta*(varphi/mu)^(2*p)*p)/((m^4*(Zeta*kappa^2*varphi^2-1)*(varphi/mu)^p+(-Zeta*kappa^2*varphi^2+1)*m^4+24*Zeta*varphi*kappa^2)*(-1+(varphi/mu)^p))

(7)

N:=evalf(int((3*V1*kappa^2*((2*V*V1)/3 - f1^2*V1*R/(3*V) - f1*V1^2/(3*V))/(V*(-f*kappa^2 + 1)*(-R*f1 - 2*V1))),varphi=varphi__hc..varphi__end)assuming varphi__hc > 0, varphi__hc > varphi__end);

-1.*(int(-3.*(varphi/mu)^p*p*kappa^2*(-.6666666667*m^8*(1.-1.*(varphi/mu)^p)*(varphi/mu)^p*p/varphi+5.333333333*Zeta^2*varphi*m^4*(varphi/mu)^p*p*kappa^2*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p)*(1.-1.*(varphi/mu)^p))-.6666666667*Zeta*m^4*((varphi/mu)^p)^2*p^2/(varphi*(1.-1.*(varphi/mu)^p)))/(varphi*(1.-1.*(varphi/mu)^p)*(-1.*Zeta*kappa^2*varphi^2+1.)*(-8.*kappa^2*m^4*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)*Zeta*varphi/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p))+2.*m^4*(varphi/mu)^p*p/varphi)), varphi = varphi__end .. varphi__hc))

(8)

simplify(-1.*(int(-3.*(varphi/mu)^p*p*kappa^2*(-.6666666667*m^8*(1.-1.*(varphi/mu)^p)*(varphi/mu)^p*p/varphi+5.333333333*Zeta^2*varphi*m^4*(varphi/mu)^p*p*kappa^2*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p)*(1.-1.*(varphi/mu)^p))-.6666666667*Zeta*m^4*((varphi/mu)^p)^2*p^2/(varphi*(1.-1.*(varphi/mu)^p)))/(varphi*(1.-1.*(varphi/mu)^p)*(-1.*Zeta*kappa^2*varphi^2+1.)*(-8.*kappa^2*m^4*(-3.*(varphi/mu)^(2.*p)*m^4+(varphi/mu)^(3.*p)*m^4+3.*(varphi/mu)^p*m^4-1.*m^4-2.*Zeta*(varphi/mu)^p*p+2.*Zeta*(varphi/mu)^(2.*p)*p)*Zeta*varphi/((m^4*(Zeta*kappa^2*varphi^2-1.)*(varphi/mu)^p+(-1.*Zeta*kappa^2*varphi^2+1.)*m^4+24.*Zeta*varphi*kappa^2)*(-1.+(varphi/mu)^p))+2.*m^4*(varphi/mu)^p*p/varphi)), varphi = varphi__end .. varphi__hc)))

Error, (in content/content) invalid arguments

 

NULL

Download ex.mw

Can anyone help me factor this thing out, so I ll get an irreductible result?

x2 := 2*u - 2/3*(a - 1)*(a + 1)*u^3 + (26/45*a^4 - 4/9*a^2 + 26/45)*u^5 + O(u^6)

In an old question, @mbras asked for a "partial" `convert/elsymfun`. However, SymPy's sympy.polys.rings.PolyElement.symmetrize seems to provide more examples that cannot be handled by the program that appeared in that question.
For instance, 

>>> from sympy import var
>>> var('x:z,p:r')
(x, y, z, p, q, r)
>>> from sympy.polys.polyfuncs import symmetrize
>>> symmetrize(x**2-(y**2+2**z),[y,x],formal=True,symbols=[p+p,q*q])[0]
-2**z - 4*p**2 + 2*q**2
>>> symmetrize(x*x*y+y*y*z+z*z*x,[y,x,z],formal=True,symbols=[p,q,r])
(0, x**2*y + x*z**2 + y**2*z, [(p, x + y + z), (q, x*y + x*z + y*z), (r, x*y*z)])

Though I can , can't the built-in  be generalized to such expressions (in other words, write the polynomial part of input as a symmetric part and a remainder with (named, if need be) elementary symmetric polynomials)?

Besides, since any symmetric polynomial can also be expressed in terms of the complete symmetric polynomials, is there a similar  command in Maple?

The uploaded worksheet begins to uniformly tile the Poincare disk with pentagons using hyperbolic reflection .

Although relatively easy to create the central pentagon and the first adjacent pentagon, it becomes increasingly difficult to determine which lines to reflect to create the remaining pentagons in the first tier adjacent to the central pentagon and more so to create the pentagons of the second tier adjacent to those in the first tier and so on.

Is there a better technique for accomplishing this?

In particular can Mobius tranformations be employed to do this? If so, please replay with or point to a working example of this for me to follow.

 Tile_Poincare_disk.mw

Sorry, I forgot that respondents to this question must establich their own link to the DirectSearch package.

I was trying to fill a Submit Software Change Request form a couple of times (with an interval of a couple of days) to report a small issue in Maple2023, which happens when I try to open an empty mpl-file. However, each time I received an error message. It looks like it is just broken.

Does anyone know if there is any reliable mechanism to provide feedback on MapleSoft products?

Why does _EnvLinalg95 only affect  (and ) and not and ? 
 

restart;

m := <3 , 4 | 4 , 3>;

m := Matrix(2, 2, {(1, 1) = 3, (1, 2) = 4, (2, 1) = 4, (2, 2) = 3})

(1)

LinearAlgebra:-Eigenvalues(m);

Vector(2, {(1) = 7, (2) = -1})

(2)

LinearAlgebra:-Eigenvectors(m);

Vector(2, {(1) = -1, (2) = 7}), Matrix(2, 2, {(1, 1) = -1, (1, 2) = 1, (2, 1) = 1, (2, 2) = 1})

(3)

LinearAlgebra:-EigenConditionNumbers(m);

Vector(2, {(1) = 1.00000000000000, (2) = 1.00000000000000}), Vector(2, {(1) = 8., (2) = 8.})

(4)

_EnvLinalg95 := true:

whattype(m);

Matrix

(5)

LinearAlgebra:-Eigenvalues(m);

Vector(2, {(1) = 7, (2) = -1})

(6)

LinearAlgebra:-Eigenvectors(m):

Error, (in Matrix) invalid input: `Matrix/MakeInit` expects its 1st argument, initializer, to be of type list(list), but received [proc (i, j) options operator, arrow; `if`(j = 1 and i <= 2, (Vector(2, {(1) = 1, (2) = 1}))[i], rhs(fill_opt)) end proc]

 

LinearAlgebra:-EigenConditionNumbers(m);

Vector(2, {(1) = 1.00000000000000, (2) = 1.00000000000000}), Vector(2, {(1) = 8., (2) = 8.})

(7)

_EnvLinalg95 := false:

LinearAlgebra:-Eigenvectors(m);

Vector(2, {(1) = -1, (2) = 7}), Matrix(2, 2, {(1, 1) = -1, (1, 2) = 1, (2, 1) = 1, (2, 2) = 1})

(8)


 

Download _EnvLinalg95.mw

I have read the help page of Eigenvectors but couldn't find anything related.

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