Maple 2024 Questions and Posts

How do polarplot ?...

Asked by: salim-barzani 205

11 hours ago

0 0

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Warning, A new binding for the name `gamma` has been created. The global instance of this name is still accessible using the :- prefix, :-`gamma`. See ?protect for details.

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sol3 := sqrt(2)*sqrt(-tau*gamma)*tanh(x-tau*t^alpha/alpha)*exp(I*gamma*(x+((2*gamma^3*tau-4*gamma*tau+8*tau^2)/(2*gamma^2)-tau*gamma)*t^alpha/((gamma-2*tau)*alpha)))/gamma

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{alpha, gamma, t, tau, x}

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>	P := [ alpha=1, gamma=-2, tau=3]

(1)

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polar(2^(1/2)*abs(tau*gamma)^(1/2)*exp(-Im(gamma*(x+((1/2)*(2*gamma^3*tau-4*gamma*tau+8*tau^2)/gamma^2-tau*gamma)*t^alpha/((gamma-2*tau)*alpha))))*abs(tanh(x-tau*t^alpha/alpha)/gamma), argument((-tau*gamma)^(1/2)*tanh(x-tau*t^alpha/alpha)*exp(I*gamma*(x+((1/2)*(2*gamma^3*tau-4*gamma*tau+8*tau^2)/gamma^2-tau*gamma)*t^alpha/((gamma-2*tau)*alpha)))/gamma))

(2)

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Download polar.mw

How to use HodgeStar command for forms on Lie Alge...

Asked by: GeometerFromHell 0

21 hours ago

0 0

I want to calculate Hodge Star of forms on a solvable Lie algebra L, I have defined a metric tensor g on it. But when I use that g to compute the Hodge Star of an operator it tells me that the g is not a metric tensor.

with(DifferentialGeometry);
with(LieAlgebras);
A := Matrix(4, 4, [[A__11, A__12, A__13, A__14], [A__21, -A__11, A__23, A__24], [-A__24, -A__23, -A__11, A__21], [-A__14, -A__13, A__12, A__11]]);
x := [x__1, x__2, x__3, x__4, x__5, x__6];
StructureEquations := [[x[6], x[1]] = a*x[1], [x[6], x[2]] = add(A[1, i]*x[i + 1], i = 1 .. 4), [x[6], x[3]] = add(A[2, i]*x[i + 1], i = 1 .. 4), [x[6], x[4]] = add(A[3, i]*x[i + 1], i = 1 .. 4), [x[6], x[5]] = add(A[4, i]*x[i + 1], i = 1 .. 4)];
L := LieAlgebraData(StructureEquations, [x[1], x[2], x[3], x[4], x[5], x[6]], Alg1);
DGsetup(L);
with(Tensor);
e := [e1, e2, e3, e4, e5, e6];
theta := [theta1, theta2, theta3, theta4, theta5, theta6];
omega := evalDG(add(theta[i] &wedge theta[7 - i], i = 1 .. 3));
g := evalDG(add(theta[i] &t theta[7 - i], i = 1 .. 3));
HodgeStar(g, theta1)

It is showing the following error,

Error, (in DifferentialGeometry:-Tensor:-HodgeStar) expected 1st argument to be a metric tensor. Received: _DG([["tensor", Alg1, [["cov_bas", "cov_bas"], []]], [`...`]])

How can I correct this? If not is there an alternative of doing what I am trying to do?

why march('extractfile',...) shows the .m file con...

Asked by: nm 10416

Yesterday at 10:49 PM

0 0

I am trying to look at source code of one Maple application to learn it. The application is old and uses .lib and .ind files and not the new .mla files to store the code.

When I use the command march('list',path_to_lib), it shows the .m files there OK.

Next, when I use the command march('extractfile',path_to_lib,member_name.m,file_name_to_extract_to.m)

And then look at file_name_to_extract_to.m created in text editor, it is a binary and not plain text.

But when I do print(member_name), in the worksheet, Maple prints the source code on the screen OK.

Below is worksheet to show this. All what you need to run this is download the zip file to your C:/TMP/ folder (or any other folder of your choice).

https://www.maplesoft.com/applications/download.aspx?id=123874/an_extension_of_prelle-singer_method_and_maple_implementatio.zip

When you unzip the above file, you will see maple.lib, maple.ind, and maple.hdb files.

I changed the names to PS.lib, PS.ind and PS.hdb (not to conflict with any maple own files).

So my C:/TMP/ folder now have these 3 files PS.lib, PS.ind and PS.hdb in it.

Then I opened worksheet and did the following

Download why_extract_not_working.mw

Now when opening the extracted file PSIntFac.m it shows this (in the folder C:/TMP/)

M7R0
I)PSIntFacf*6$%$odeG%"nG6*%%baseG%'intfacG%0subs_Us_by_funcG%"xG%"yG%"MG%"NG%#e
qG6"F0C09%>8$-%#PSG6$9"%(PSBasisG>8&-%$mapG6$f*6#%"uGF06$%)operatorG%&arrowGF0/
-%$rhsG6#9$-%$lhsGFHF0F0F0F4>8%7#-F66$F8F"@$/FM7#%IWe~could~not~find~an~integra
ting~factor.G-%'RETURNG6#FT>8'&FM6#""#>8(&FM6#""$>8)-%%subsG6$F;&FM6#""%>8*-F_o
6$F;&FM6#""&>8+/-%%diffG6$-Fhn6#FYFY-F_o6$/FhnFap*&F]o"""Feo!""-%&printG6#%:For
~the~FOODE~in~the~formG-Fjp6#F\p-Fjp6#%?the~integrating~factor~will~beG>FM-%'no
rmalG6#-F_o6$F;&FM6#FgpF0F0F0F0

It seems Maple kepts the .m file in binary form. Is it not supposed to convert it to plain text readable form, as the one which shows when using the command print() on the screen?

Is there another march command to extract the .m files in plain text form? I looked at help of march, but see nothing so far.

If this is how march extractfile is supposed to work, then is there another way to extract in plain text?

Bug report: ODESteps gives invalid input when th...

Asked by: nm 10416

January 18 2025

1 0

There seems to be parsing problem with ODESteps. This input diff(y(x),x)=x^2*sqrt(y(x)) - y(x) gives invalid input error, but diff(y(x),x)=x^2*sqrt(y(x)) does not.

Everything else the same.

Worksheet below.

Download ode_steps_parsing_problem_jan_17_2025.mw

How do complicated substitution in ode?...

Asked by: salim-barzani 205

January 17 2025

1 0

i try to get same result by substituation but i don't know what is mistake after i take second derivative is wronge i don't know how get same result as in paper did can anyone help to calculate this part is not hard but is complicated ,How calculated second derivative and put in our ode to get the parameters?

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F := U(xi) = sum(tanh(xi)^(i-1)*(B[i]*sech(xi)+A[i]*tanh(xi)), i = 1 .. n)+A[0]

U(xi) = sum(tanh(xi)^(i-1)*(B[i]*sech(xi)+A[i]*tanh(xi)), i = 1 .. n)+A[0]

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S := U(f(xi)) = sum(cos(f(xi))^(i-1)*(B[i]*sin(f(xi))+A[i]*cos(f(xi))), i = 1 .. n)+A[0]

U(f(xi)) = sum(cos(f(xi))^(i-1)*(B[i]*sin(f(xi))+A[i]*cos(f(xi))), i = 1 .. n)+A[0]

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Download complex-issue.mw

why Maple hangs on dsolve on this first order ode?...

Asked by: nm 10416

January 17 2025

0 1

Maple dsolve hangs (mserver.exe runs with high CPU for long time, had to stop it).

This question is, why does it hang? As this can indicate internal logic bug.

This question is not why Maple can't solve this ode (taken from old textbook) as not solving an ode is not a bug (even though it should, as Maple is very good in solving ode's) but hanging is a bug.

infolvel shows it hangs when it reaches

<- Abel successful
         equivalence to an Abel ODE successful, Abel ODE has been solved

And stops here.

Here is worksheet, showing the attempts made, and verifying book solution is correct using Maple with change of variable.

Make sure to save all your work before trying this just to be safe.

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restart;

>	interface(version);

>	Physics:-Version();

>	original_ode :=(diff(y(x),x)x-y(x))(x-diff(y(x),x)y(x))=2diff(y(x),x);

>	#infolevel[dsolve]:=5; dsolve(original_ode); #hangs

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restart;

>	original_ode :=(diff(y(x),x)x-y(x))(x-diff(y(x),x)y(x))=2diff(y(x),x); dsolve(original_ode,'implicit'); #hangs

>	restart; #ONE SOLUTION IS:

>	original_ode:=(diff(y(x),x)x-y(x))(x-diff(y(x),x)y(x))=2diff(y(x),x); book_sol:=y(x)=sqrt(x^2c__1+2c__1/(c__1-1)); odetest(book_sol,original_ode)

y(x) = (x^2*c__1+2*c__1/(c__1-1))^(1/2)

workaround to solve, by change of variables

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restart;

>	original_ode :=(diff(y(x),x)x-y(x))(x-diff(y(x),x)y(x))=2diff(y(x),x); ode2:=PDEtools:-dchange({x=sqrt(u),y(x)=sqrt(v(u))},original_ode,[v(u),u]): sol:=dsolve(ode2): sol:=map(X->eval(X,[v(u)=y(x)^2,u=x^2]),[sol]); map(X->odetest(X,original_ode),sol)

[y(x)^2 = x^2+2-2*2^(1/2)*(x^2)^(1/2), y(x)^2 = x^2+2+2*2^(1/2)*(x^2)^(1/2), y(x)^2 = c__1*x^2+2*c__1/(c__1-1)]

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Download why_dsolve_hangs_jan_17_2025.mw

Open dialogue stops working. Unable to select file...

Asked by: nm 10416

January 12 2025

3 2

This is a very serious problem. Maple 2024.2 on windows 10.

I noticed, may be starting 2-3 weeks now, that sometimes when I do File->Open , and the Open dialogue opens, I am not able to use the mouse to select the .mw file I want to open.

Can not even close the dialogue by clicking X. Even clickiing on cancel does nothing. Basically the mouse seems not doing anything.

Only way is to type using the keyboard the file name. Eveything else does not work.

Not only that, the mouse is trapped in the dialogue.

I can't even get it out of Maple to go to another application. AT first, I had to do CTRL-ALT-DEL to get out and use the task manager to kill Maple. Then later I found if I type the file name I can get out.

Here is a movie.

I do not understand what is causing this. This only happens in Maple for me. Neven seen anything like this before.

Any suggestions what to look for?

I just remembered. 2-3 weeks ago, I closed the left panel. As you see above.

I just tried now, and expanded it again, and guess what, the mouse seems to be working now!

Can someone conform this? Here is a movie with the panel expanded again:

You see, the mouse now works and can select files.

When I minimize the left panel, the mouse sometimes stops working in file dialogue.

Here is another movie showing this problem much more clearly.

When closing the left panel, the open file dialogue stops working (mouse not working), and when expanding it again, it starts to work!

This can not be a feature right? it must be a bug in the Java interface?

why my pdetest not satisfy?...

Asked by: salim-barzani 205

January 10 2025

0 11

every thing is correct but i dont know why my PDE is not be zero, i did by another way is satidy but i change whole equation by sabstitutiin then i did ode test is satisfy by putting case in equation and solution with condition but when i want to use pdetest test in pde is not satisfy ?

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NULL

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lambda := -tau/c; epsilon := -tau/c; delta := (2*c^2-gamma*tau)/(gamma-2*tau)

(2*c^2-gamma*tau)/(gamma-2*tau)

(4)

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case1 := [c = RootOf(-gamma^3*tau+2*_Z^2+2*gamma*tau-4*tau^2)/gamma, A[0] = 0, A[1] = RootOf(_Z^2*gamma+2*tau), B[1] = 0]

[c = RootOf(-gamma^3*tau+2*_Z^2+2*gamma*tau-4*tau^2)/gamma, A[0] = 0, A[1] = RootOf(_Z^2*gamma+2*tau), B[1] = 0]

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Omega(x, t) = -RootOf(_Z^2*gamma+2*tau)*tanh(t*tau-x)*exp(I*gamma*((2*c^2-gamma*tau)*t/(gamma-2*tau)+x))

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pde1 := I*(diff(Omega(x, t), `$`(t, 2))-c^2*(diff(Omega(x, t), `$`(x, 2))))+diff(U(-t*tau+x)^2*Omega(x, t), t)-lambda*c*(diff(U(-t*tau+x)^2*Omega(x, t), x))+(1/2)*(diff(Omega(x, t), `$`(x, 2), t))-(1/2)*epsilon*c*(diff(Omega(x, t), `$`(x, 3))) = 0

I*(diff(diff(Omega(x, t), t), t)-c^2*(diff(diff(Omega(x, t), x), x)))-2*U(-t*tau+x)*Omega(x, t)*(D(U))(-t*tau+x)*tau+U(-t*tau+x)^2*(diff(Omega(x, t), t))+tau*(2*U(-t*tau+x)*Omega(x, t)*(D(U))(-t*tau+x)+U(-t*tau+x)^2*(diff(Omega(x, t), x)))+(1/2)*(diff(diff(diff(Omega(x, t), t), x), x))+(1/2)*tau*(diff(diff(diff(Omega(x, t), x), x), x)) = 0

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I*(diff(diff(Omega(x, t), t), t)-RootOf(-gamma^3*tau+2*_Z^2+2*gamma*tau-4*tau^2)^2*(diff(diff(Omega(x, t), x), x))/gamma^2)-2*U(-t*tau+x)*Omega(x, t)*(D(U))(-t*tau+x)*tau+U(-t*tau+x)^2*(diff(Omega(x, t), t))+tau*(2*U(-t*tau+x)*Omega(x, t)*(D(U))(-t*tau+x)+U(-t*tau+x)^2*(diff(Omega(x, t), x)))+(1/2)*(diff(diff(diff(Omega(x, t), t), x), x))+(1/2)*tau*(diff(diff(diff(Omega(x, t), x), x), x)) = 0

(8)

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(1/2)*(2*gamma^2*(tau*(diff(Omega(x, t), x))+diff(Omega(x, t), t))*U(-t*tau+x)^2+(diff(diff(diff(Omega(x, t), t), x), x))*gamma^2+tau*(diff(diff(diff(Omega(x, t), x), x), x))*gamma^2-(4*I)*((1/4)*gamma^3+tau-(1/2)*gamma)*tau*(diff(diff(Omega(x, t), x), x))+(2*I)*(diff(diff(Omega(x, t), t), t))*gamma^2)/gamma^2 = 0

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Download pdetest.mw

How make a system of equation by using special fa...

Asked by: salim-barzani 205

January 06 2025

0 4

i want to factoring the (m+G'/G) in my long equation but i use some trick but still i can't get the exactly system and still G will remain in my system what should i factoring for remove this G(xi) from my system is all about factoring , my system of equation are wrong contain G(xi) How i can remove it by taking a factoring or any other technique,

not parameter is arbitrary except V and sigma''

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Warning, A new binding for the name `gamma` has been created. The global instance of this name is still accessible using the :- prefix, :-`gamma`. See ?protect for details.

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F := sum(e[i]*(m+(diff(G(xi), xi))/G(xi))^i, i = -1 .. 1)

e[-1]/(m+(diff(G(xi), xi))/G(xi))+e[0]+e[1]*(m+(diff(G(xi), xi))/G(xi))

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-e[-1]*((diff(diff(G(xi), xi), xi))/G(xi)-(diff(G(xi), xi))^2/G(xi)^2)/(m+(diff(G(xi), xi))/G(xi))^2+e[1]*((diff(diff(G(xi), xi), xi))/G(xi)-(diff(G(xi), xi))^2/G(xi)^2)

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-e[-1]*((-(2*m*mu+lambda)*(diff(G(xi), xi))-mu)/G(xi)-(diff(G(xi), xi))^2/G(xi)^2)/(m+(diff(G(xi), xi))/G(xi))^2+e[1]*((-(2*m*mu+lambda)*(diff(G(xi), xi))-mu)/G(xi)-(diff(G(xi), xi))^2/G(xi)^2)

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NULL

>	# rewritting rule RR := isolate(m+diff(G(xi), xi)/(G(xi))=Phi, diff(G(xi), xi)/G(xi));

(diff(G(xi), xi))/G(xi) = Phi-m

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>	# Apply RR and collect wrt Phi subs(RR, L): normal(%): PhiN := collect(numer(lhs(%)), phi): PhiD := denom(lhs(%%));

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>	with(LargeExpressions): LLE := collect(PhiN, Phi, Veil[phi] ): LLE / PhiD = 0;

(Phi^6*phi[1]+3*Phi^5*phi[2]-Phi^4*phi[3]-Phi^3*phi[4]-Phi^2*phi[5]+Phi*phi[6]-phi[7])/(Phi^3*G(xi)^4) = 0

(15)

>	# phi[i] coefficients phis := [ seq( phi[i] = simplify(Unveil[phi](phi[i]), size), i=1..LastUsed[phi] ) ]: print~( phis ):

phi[3] = -3*e[1]*G(xi)^4*(-(1/3)*a[1]*k^2+(-e[-1]*(gamma-sigma)*e[1]+(-gamma+sigma)*e[0]^2+(1/3)*w*a[2]-(1/3)*alpha)*k+b*e[-1]*e[1]+b*e[0]^2-(1/3)*w)

phi[4] = (2*e[1]*(V*a[2]-a[1])*(diff(G(xi), xi))^3+3*e[1]*G(xi)*(2*m*mu+lambda)*(V*a[2]-a[1])*(diff(G(xi), xi))^2+e[1]*(V*a[2]-a[1])*G(xi)*((2*m*mu+lambda)^2*G(xi)+3*mu)*(diff(G(xi), xi))+G(xi)^2*(-(6*e[-1]*((-gamma+sigma)*k+b)*e[1]-a[1]*k^2+k*w*a[2]+((-gamma+sigma)*k+b)*e[0]^2-k*alpha-w)*e[0]*G(xi)+e[1]*mu*(2*m*mu+lambda)*(V*a[2]-a[1])))*G(xi)

phi[5] = -3*e[-1]*G(xi)^4*(-(1/3)*a[1]*k^2+(-e[-1]*(gamma-sigma)*e[1]+(-gamma+sigma)*e[0]^2+(1/3)*w*a[2]-(1/3)*alpha)*k+b*e[-1]*e[1]+b*e[0]^2-(1/3)*w)

phi[6] = 4*((1/2)*(V*a[2]-a[1])*(diff(G(xi), xi))^3+(3/2)*(V*a[2]-a[1])*(m*mu+(1/2)*lambda)*G(xi)*(diff(G(xi), xi))^2+(V*a[2]-a[1])*((m*mu+(1/2)*lambda)^2*G(xi)+(3/4)*mu)*G(xi)*(diff(G(xi), xi))+(1/2)*((3/2)*e[0]*((-gamma+sigma)*k+b)*e[-1]*G(xi)+(V*a[2]-a[1])*(m*mu+(1/2)*lambda)*mu)*G(xi)^2)*e[-1]*G(xi)

phi[7] = 8*e[-1]*((1/4)*(V*a[2]-a[1])*(diff(G(xi), xi))^4+(V*a[2]-a[1])*(m*mu+(1/2)*lambda)*G(xi)*(diff(G(xi), xi))^3+(V*a[2]-a[1])*((m*mu+(1/2)*lambda)^2*G(xi)+(1/2)*mu)*G(xi)*(diff(G(xi), xi))^2+(V*a[2]-a[1])*(m*mu+(1/2)*lambda)*mu*G(xi)^2*(diff(G(xi), xi))+(1/4)*(-(1/2)*((-gamma+sigma)*k+b)*e[-1]^2*G(xi)^2+mu^2*(V*a[2]-a[1]))*G(xi)^2)

(16)

>	# WATCHOUT: you have 9 coefficients and so its desirable to have the same number of unknowns unknowns := indets(rhs~(phis), {e[-1],e[0],e[1],'identical'(mu),'identical'(lambda),'identical'(a[1]),'identical'(alpha)}); COEFFS := solve(rhs~(phis), unknowns)

${alpha = alpha, lambda = lambda, mu = mu, a[1] = a[1], e[-1] = 0, e[0] = 0, e[1] = 0}, {alpha = alpha, lambda = lambda, mu = mu, a[1] = -(gamma*k*e[0]^2-k*sigma*e[0]^2-b*e[0]^2-k*w*a[2]+alpha*k+w)/k^2, e[-1] = 0, e[0] = e[0], e[1] = 0}, {alpha = (1/2)*(-G(xi)^4*gamma*k^3*e[-1]^2+G(xi)^4*k^3*sigma*e[-1]^2-4*G(xi)^2*(diff(G(xi), xi))*V*k^2*m*mu^2*a[2]+4*G(xi)*(diff(G(xi), xi))^3*V*k^2*m*mu*a[2]+G(xi)^4*b*k^2*e[-1]^2+4*G(xi)^2*(diff(G(xi), xi))*k*m*mu^2*w*a[2]-4*G(xi)*(diff(G(xi), xi))^3*k*m*mu*w*a[2]-2*G(xi)^2*V*k^2*mu^2*a[2]+2*G(xi)*(diff(G(xi), xi))^2*V*k^2*mu*a[2]-2*G(xi)*(diff(G(xi), xi))*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*V*k^2*mu*a[2]+2*(diff(G(xi), xi))^4*V*k^2*a[2]+2*(diff(G(xi), xi))^3*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*V*k^2*a[2]-4*G(xi)^2*(diff(G(xi), xi))*m*mu^2*w+2*G(xi)^2*k*mu^2*w*a[2]+4*G(xi)*(diff(G(xi), xi))^3*m*mu*w-2*G(xi)*(diff(G(xi), xi))^2*k*mu*w*a[2]+2*G(xi)*(diff(G(xi), xi))*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*k*mu*w*a[2]-2*(diff(G(xi), xi))^4*k*w*a[2]-2*(diff(G(xi), xi))^3*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*k*w*a[2]-2*G(xi)^2*mu^2*w+2*G(xi)*(diff(G(xi), xi))^2*mu*w-2*G(xi)*(diff(G(xi), xi))*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*mu*w+2*(diff(G(xi), xi))^4*w+2*(diff(G(xi), xi))^3*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*w)/((2*m*mu^2*(diff(G(xi), xi))*G(xi)^2-2*m*mu*(diff(G(xi), xi))^3*G(xi)+mu*(diff(G(xi), xi))*G(xi)*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)-(diff(G(xi), xi))^3*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)+mu^2*G(xi)^2-mu*(diff(G(xi), xi))^2*G(xi)-(diff(G(xi), xi))^4)*k), lambda = RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)/G(xi), mu = mu, a[1] = -(1/2)*(-G(xi)^4*gamma*k*e[-1]^2+G(xi)^4*k*sigma*e[-1]^2-4*G(xi)^2*(diff(G(xi), xi))*V*m*mu^2*a[2]+4*G(xi)*(diff(G(xi), xi))^3*V*m*mu*a[2]+G(xi)^4*b*e[-1]^2-2*G(xi)^2*V*mu^2*a[2]+2*G(xi)*(diff(G(xi), xi))^2*V*mu*a[2]-2*mu*G(xi)*(diff(G(xi), xi))*V*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*a[2]+2*(diff(G(xi), xi))^4*V*a[2]+2*(diff(G(xi), xi))^3*V*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)*a[2])/(2*m*mu^2*(diff(G(xi), xi))*G(xi)^2-2*m*mu*(diff(G(xi), xi))^3*G(xi)+mu*(diff(G(xi), xi))*G(xi)*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)-(diff(G(xi), xi))^3*RootOf(4*m^2*mu^2*(diff(G(xi), xi))*G(xi)^2+2*m*mu^2*G(xi)^2+6*m*mu*(diff(G(xi), xi))^2*G(xi)+3*mu*(diff(G(xi), xi))*G(xi)+2*(diff(G(xi), xi))^3+(4*m*mu*(diff(G(xi), xi))*G(xi)+mu*G(xi)+3*(diff(G(xi), xi))^2)*_Z+(diff(G(xi), xi))*_Z^2)+mu^2*G(xi)^2-mu*(diff(G(xi), xi))^2*G(xi)-(diff(G(xi), xi))^4), e[-1] = e[-1], e[0] = 0, e[1] = 0}$

(17)

>	case1 := COEFFS[2]

${alpha = alpha, lambda = lambda, mu = mu, a[1] = -(gamma*k*e[0]^2-k*sigma*e[0]^2-b*e[0]^2-k*w*a[2]+alpha*k+w)/k^2, e[-1] = 0, e[0] = e[0], e[1] = 0}$

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>

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>

(-a[2]*V-(gamma*k*e[0]^2-k*sigma*e[0]^2-b*e[0]^2-k*w*a[2]+alpha*k+w)/k^2)*(diff(diff(U(xi), xi), xi))+U(xi)*(((-gamma+sigma)*k+b)*U(xi)^2+k*e[0]^2*gamma-k*e[0]^2*sigma-b*e[0]^2-k*w*a[2]+k*alpha+(w*a[2]-alpha)*k) = 0

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>

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>

E := diff(G(xi), xi) = -(-2*m*mu-lambda)*exp(-(2*m*mu+lambda)*xi)*c__1/(2*m*mu+lambda)-mu/(2*m*mu+lambda)

diff(G(xi), xi) = -(-2*m*mu-lambda)*exp(-(2*m*mu+lambda)*xi)*c__1/(2*m*mu+lambda)-mu/(2*m*mu+lambda)

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>

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>

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>

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>

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>

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Download G-factoring.mw

bug report. convert(..,y_x) converts non equation ...

Asked by: nm 10416

January 05 2025

1 0

I found that convert(ode,y_x) converts the input ode, when it is NOT an equation, to an equation.

sometimes and sometimes not.

For example, convert(diff(y(t),t)+y(t)-t,y_x) gives diff(t(y), y) = 1/(t(y) - y)

Notice the input is not an equation. Maple adds = and makes an equation in the output.

This can cause no problem if it works like this in all cases. But if the input has piecewise, then Maple no longer does the same and keep the output as not an equation.

I found this by accident, as my code was doing lhs() on the result of convert, and that always worked, except when I used an ode with piecewise.

This behaviour is not consistent. Maple should either always convert output to equation for all input or not convert. It should not do it for some input and not the other.

Actually, the best behaviour is for the software to reject the input in first place if it is not an equation.

Worksheet below.

>	interface(version);

>	Physics:-Version();

>

libname;

$"C:\Users\Owner\maple\toolbox\2024\Physics Updates\lib", "C:\Program Files\Maple 2024\lib"$

>	#this works even when there is no equation in input, but the result is equation ode:=diff(y(t),t)+y(t)-t; convert(ode,y_x,y(t))

>	ode:=diff(y(t),t)+y(t)-t=0; #this gives same result as above. convert(ode,y_x,y(t))

>	#but now if the input is not equation, the output is not equation. Why #did it not do the same as above?? ode:=diff(y(t),t)+y(t)-piecewise(0<=t and t<=1,2,t>1,0); convert(ode,y_x,y(t))

ode := diff(y(t), t)+y(t)-piecewise(0 <= t and t <= 1, 2, 1 < t, 0)

1/(diff(t(y), y))+y-piecewise(0 <= t(y) and t(y) <= 1, 2, 1 < t(y), 0)

Download strange_behaviour_of_convert_yx_jan_5_20225.mw

system of 1-D PDEs numerically...

Asked by: mayzal 25

January 05 2025

1 8

I’m trying to solve a stiff system 1-D PDEs numerically in Maple but I’m getting the following error:

“Error, (in pdsolve/numeric/match_PDEs_BCs) cannot handle systems with multiple PDE describing the time dependence of the same dependent variable, or having no time dependence”

I included a picture of the PDEs and their BCs in the attached maple file. For easy reading, the attached file includes highlighted sections for parameters and variables. You can skip those to PDEs, BCs and ICs sections at the end of the document to reach the error I’m facing.

For reference, I used another software to solve the system and I was able to get the results in few seconds, so I think it is solvable. However, personally I prefer to use Maple so any inputs, insights, workarounds that I could use to handle the system in Maple would be of great help to me. Thank you.

question.mw

Bug report: Error, (in dsolve) invalid subscript s...

Asked by: nm 10416

December 27 2024

0 2

I do not remember if I reported this before or not. Can't find it. Just in case, I am posting this.

If someone find it is duplicate, feel free to delete this. But this is in latest Maple 2024.2. May be this can be fixed in time by Maple 2025 version.

>

restart;

>	interface(version);

>	Physics:-Version();

>

libname;

$"C:\Users\Owner\maple\toolbox\2024\Physics Updates\lib", "C:\Program Files\Maple 2024\lib"$

>	ode := diff(y(x),x)/y(x)-(3(4x^2+y(x)^2+1))/(2x(4x^2+y(x)^2-2-2x))=0;

(diff(y(x), x))/y(x)-(3/2)*(4*x^2+y(x)^2+1)/(x*(4*x^2+y(x)^2-2-2*x)) = 0

>	DEtools:-odeadvisor(ode);

>	dsolve(ode,y(x));

Error, (in dsolve) invalid subscript selector

>

restart;

>	infolevel[dsolve]:=5;

>	ode := diff(y(x),x)/y(x)-(3(4x^2+y(x)^2+1))/(2x(4x^2+y(x)^2-2-2x))=0:

>	dsolve(ode,y(x));

Methods for first order ODEs:

--- Trying classification methods ---

trying a quadrature

trying 1st order linear

trying Bernoulli

trying separable

trying inverse linear

trying homogeneous types:

trying Chini

differential order: 1; looking for linear symmetries

trying exact

Looking for potential symmetries

trying inverse_Riccati

trying an equivalence to an Abel ODE

equivalence obtained to this Abel ODE: diff(y(x),x) = 3/2*(4*x^2+1)/x/(2*x^2-x-1)*y(x)-(x^2+2*x+3)/x/(2*x^2-x-1)^2*y(x)^2+3/8*(2*x+3)/(2*x^2-x-1)^3/x*y(x)^3

trying to solve the Abel ODE ...

The relative invariant s3 is: -1/432*(8*x^4+40*x^3+45*x^2-270*x+135)/x^3/(x-1)^6/(2*x+1)^4

The first absolute invariant s5^3/s3^5 is: 729/16*(128*x^8+1152*x^7+3696*x^6+1744*x^5+8148*x^4-31500*x^3+6615*x^2-5670*x+8505)^3/(2*x+1)^4/(8*x^4+40*x^3+45*x^2-270*x+135)^5

The second absolute invariant s3*s7/s5^2 is: 1/3*(8*x^4+40*x^3+45*x^2-270*x+135)*(10240*x^12+133120*x^11+697600*x^10+1710080*x^9+3358592*x^8-1701568*x^7+6692592*x^6-18182448*x^5+2088072*x^4-7938000*x^3+2525985*x^2+1786050*x+2679075)/(128*x^8+1152*x^7+3696*x^6+1744*x^5+8148*x^4-31500*x^3+6615*x^2-5670*x+8505)^2

...checking Abel class AIL (45)

...checking Abel class AIL (310)

...checking Abel class AIR (36)

...checking Abel class AIL (301)

...checking Abel class AIL (1000)

...checking Abel class AIL (42)

...checking Abel class AIL (185)

...checking Abel class AIA (by Halphen)

...checking Abel class AIL (205)

...checking Abel class AIA (147)

...checking Abel class AIL (581)

...checking Abel class AIL (200)

...checking Abel class AIL (257)

...checking Abel class AIL (400)

...checking Abel class AIA (515)

...checking Abel class AIR (1001)

...checking Abel class AIA (201)

...checking Abel class AIA (815)

Looking for potential symmetries

... changing x -> 1/x, trying again

Looking for potential symmetries

The third absolute invariant s5*s7/s3^4 is: 243/16*(10240*x^12+133120*x^11+697600*x^10+1710080*x^9+3358592*x^8-1701568*x^7+6692592*x^6-18182448*x^5+2088072*x^4-7938000*x^3+2525985*x^2+1786050*x+2679075)/(2*x+1)^4*(128*x^8+1152*x^7+3696*x^6+1744*x^5+8148*x^4-31500*x^3+6615*x^2-5670*x+8505)/(8*x^4+40*x^3+45*x^2-270*x+135)^4

-> ======================================

-> ...checking Abel class D (by Appell)

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {4/27} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class B (by Liouville)

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {1, 4, 1/4} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class A (by Abel)

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {0, -1/4} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class C (by Abel)

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {2, -11676447873119/75975070592769, 9/5, 15632211369872/75439744512117, 46273613050865/52325357771027, 75312059745574/25138886548531} ***

-> Step 3: looking for a solution F depending on x

_____________________________

C = 9/5 leads to a useless solution (F does not depend on x)

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIL 1.6

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {-4, 16} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIL 1.8

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {0, -116457391291688/45108305127449, -96869842492381/35485755507516, -36964550865207/94238117721032, -32286830321303/11596568583712, 32286830321303/11596568583712, 36964550865207/94238117721032, 96869842492381/35485755507516, 116457391291688/45108305127449} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIL 1.9

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {-2/9, -1/9} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIA 1.51

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {0, -94917840318055/84247876515289, -85939756880989/51399391393709, -82210125508529/36853933366676, -74381886667083/82545981233858, -41168492684238/33804146399567, -15658703496425/19275443365317, -9175348901453/101481647952193, 3/4, 15/4, 5568553686203/113599855351490, 12774469621703/63437040534358, 17836021821409/102823494563886, 39657708622139/74009717243016, 82495450887526/27663991325651, 86656182727564/45157560524183, 90074893410229/54954593917906, 100200889070747/32282555481919, 113612565327585/103754255779069} ***

-> Step 3: looking for a solution F depending on x

_____________________________

C = 15/4 leads to a useless solution (F does not depend on x)

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIA 1.5

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {-1, 1, -113553630998996/78694251194667, -112790344818825/35834119404842, -104905620984375/18860524785743, -95409943222181/78810323073434, -77648002983645/31218435062578, -67259194033608/9576982470445, -46892223838816/86694928762723, -45901561561111/29768419326991, -34674701564566/6522678435631, 26154715634141/21099761863911, 42841215778132/81925179545457, 52638927823233/15127919203723, 54069389554571/5444364811188, 54445812264368/10328928623117, 56815569067370/40738034746481, 75614540760757/62881656939350, 76459718737483/64786816765621, 85896394925571/88677987470966, 90623073438172/24246571690325, 103628692054633/17857341616628, 117754725919014/60191028908095} ***

-> Step 3: looking for a solution F depending on x

_____________________________

C = -1 leads to a useless solution (F does not depend on x)

_____________________________

C = -113553630998996/78694251194667 leads to a useless solution (F does not depend on x)

_____________________________

C = -112790344818825/35834119404842 leads to a useless solution (F does not depend on x)

_____________________________

C = -104905620984375/18860524785743 leads to a useless solution (F does not depend on x)

_____________________________

C = -95409943222181/78810323073434 leads to a useless solution (F does not depend on x)

_____________________________

C = -77648002983645/31218435062578 leads to a useless solution (F does not depend on x)

_____________________________

C = -67259194033608/9576982470445 leads to a useless solution (F does not depend on x)

_____________________________

C = -46892223838816/86694928762723 leads to a useless solution (F does not depend on x)

_____________________________

C = -45901561561111/29768419326991 leads to a useless solution (F does not depend on x)

_____________________________

C = -34674701564566/6522678435631 leads to a useless solution (F does not depend on x)

_____________________________

C = 26154715634141/21099761863911 leads to a useless solution (F does not depend on x)

_____________________________

C = 42841215778132/81925179545457 leads to a useless solution (F does not depend on x)

_____________________________

C = 52638927823233/15127919203723 leads to a useless solution (F does not depend on x)

_____________________________

C = 54069389554571/5444364811188 leads to a useless solution (F does not depend on x)

_____________________________

C = 54445812264368/10328928623117 leads to a useless solution (F does not depend on x)

_____________________________

C = 56815569067370/40738034746481 leads to a useless solution (F does not depend on x)

_____________________________

C = 75614540760757/62881656939350 leads to a useless solution (F does not depend on x)

_____________________________

C = 76459718737483/64786816765621 leads to a useless solution (F does not depend on x)

_____________________________

C = 85896394925571/88677987470966 leads to a useless solution (F does not depend on x)

_____________________________

C = 90623073438172/24246571690325 leads to a useless solution (F does not depend on x)

_____________________________

C = 103628692054633/17857341616628 leads to a useless solution (F does not depend on x)

_____________________________

C = 117754725919014/60191028908095 leads to a useless solution (F does not depend on x)

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIA 1.52

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {-5, -4, -3, 0, 1, 2, -3/2} ***

-> Step 3: looking for a solution F depending on x

*** No solution F of x was found ***

-> ======================================

-> ...checking Abel class AIA 1.53

-> Step 1: checking for a disqualifying factor on F after evaluating x at a number

Trying x = 2

*** No disqualifying factor on F was found ***

-> Step 2: calculating resultants to eliminate F and get candidates for C

*** Candidates for C are {-3, -1, 1, 2, -3/2, -2/3, -1/2} ***

-> Step 3: looking for a solution F depending on x

_____________________________

C = -3 leads to a useless solution (F does not depend on x)

_____________________________

C = -3/2 leads to a useless solution (F does not depend on x)

*** No solution F of x was found ***

trying to map the Abel into a solvable 2nd order ODE

...checking Abel class AIA 2-parameter, reducible to Riccati

Error, (in dsolve) invalid subscript selector

>

restart;

>	ode := diff(y(x),x)/y(x)-(3(4x^2+y(x)^2+1))/(2x(4x^2+y(x)^2-2-2x))=0:

>	dsolve(ode,y(x));

Error, (in dsolve) invalid subscript selector

>	tracelast;

Error, (in dsolve) invalid subscript selector

Download dsolve_invalid_subscript_dec_27_2024.mw

why taking double derivative with two different in...

Asked by: salim-barzani 205

December 27 2024

0 6

I did a lot of time but this time i don't know why not run any one have idea?

>

(1)

>

(2)

>

(3)

>

(4)

>

(5)

>

Download why.mw

Error, (in dsolve) type `System` does not exist wh...

Asked by: nm 10416

December 26 2024

1 4

I am trying to see if I can get speed up by using dsolve inside thread.

I made very simple example of global list of two differential equations to start with.

Next, created two threads where each picks one ode from the global list to process. So they should in theory run in parallel. The list of ode's is a global list in the worksheet for now.

But I keep getting error when calling dsolve

Error, (in dsolve) type `System` does not exist

I tried also passing the actual ode to the thread, still, same error.

Next, I did not pass anything, but called dsolve directly from inside thread proc on same ode. The ode is local variable inside the proc. I still get same error.

Does this mean dsolve is not supported by threads?

But when I searched this subject, AI says it works in threads:

Everything works OK when I run dsolve in worksheet outside thread (i.e. normally).

I will show below worksheet showing these cases. I must not be doing something right. But what? Can one not pass data from global worksheet to the thread this way? Or does one needs to load something in each thread to make this work?

>	interface(version);

>	Physics:-Version();

>

libname;

$"C:\Users\Owner\maple\toolbox\2024\Physics Updates\lib", "C:\Program Files\Maple 2024\lib"$

Example 1. Passing index of list to thread

>

restart;

>	g_list:=[sin(t)diff(x(t),t$2)+cos(t)diff(x(t),t)+2x(t)=0, diff(y(x),x)=lambdasin(lambdax)y(x)^2+acos(lambdax)^ny(x)-acos(lambda*x)^(n-1)]:

>	work_func:=proc(i::posint) :-dsolve(g_list[i]): end proc:

>	Threads:-Wait( seq( Threads:-Create( work_func(i)), i=1..2) );

Error, (in dsolve) type `System` does not exist

Example 2. Passing actual ode itself to thread

>

restart;

>	g_list:=[sin(t)diff(x(t),t$2)+cos(t)diff(x(t),t)+2x(t)=0, diff(y(x),x)=lambdasin(lambdax)y(x)^2+acos(lambdax)^ny(x)-acos(lambda*x)^(n-1)]:

>	work_func:=proc(ode::`=`) :-dsolve(ode): end proc:

>	Threads:-Wait( seq( Threads:-Create( work_func(g_list[i])), i=1..2) );

Error, (in dsolve) type `System` does not exist

>

Example 3. Normal processing. No threads

>

restart;

>	g_list:=[sin(t)diff(x(t),t$2)+cos(t)diff(x(t),t)+2x(t)=0, diff(y(x),x)=lambdasin(lambdax)y(x)^2+acos(lambdax)^ny(x)-acos(lambda*x)^(n-1)]:

>	work_func:=proc(ode::`=`) :-dsolve(ode): end proc:

>	for item in g_list do work_func(item); od:

>

#no error

>

Example 4. do not pass anything. Just call dsolve

>

restart;

>	work_func:=proc(i::posint) local x,t; local ode:=sin(t)diff(x(t),t$2)+cos(t)diff(x(t),t)+2*x(t)=0; :-dsolve(ode): end proc:

>	Threads:-Wait( seq( Threads:-Create( work_func(i)), i=1..2) );

Error, (in dsolve) type `System` does not exist

>

Download error_dsolve_using_threads_dec_26_2024.mw

implicitplot misbehaves in Maple 2024...

Asked by: Rouben Rostamian 8154

December 26 2024

3 5

>

restart;

Here are the graphs of a parabola and a straight line:

>	plots:-display( plot(x^2, x=-1..1), plot((x+1)/2, x=-1..1), color=["Red","Green"]);

Suppose I want to plot the part of the parabola that lies below

the straight line, and suppose, just to be nasty, I choose to do it

with implicitplot:

>	plots:-implicitplot(y=x^2, x=-1..1, y=0..(x+1)/2);

That is not a parabola at all. [And where does the "ynew" label come from?]

This behavior was introduced in Maple 2022.

In Maple 2021 we get the expected result:

plots:-implicitplot(y=x^2, x=-1..1, y=0..(x+1)/2);

Download mw.mw

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