Maple 2019 Questions and Posts

These are Posts and Questions associated with the product, Maple 2019

If I do:

df:=DataFrame(Matrix(3,4,[seq(1..12)]), rows=[a,b,c],columns=[A,B,C,D]);Tabulate(df, width=100)

 

The font that Maple uses for the Tablulate is much larger than the font used to display the Dataframe. How does one choose the font size that Tabluate() uses? 

Peter

I was trying to see if Maple can solve this problem from my class textbook

When I tried boundary conditions all zero on the Laplace PDE in semicircular cylinder, pdsolve generates internal error.

The boundary conditions should not all be zero for nontrivial solution, but the question is why Maple generate this internal error? Is this a bug? Using Physics package 362, Maple 2019 on windows 10.

restart;

unassign('r,theta,z,f,H');
pde:=VectorCalculus:-Laplacian(u(r,theta,z),'cylindrical'[r,theta,z])=0;
bc:=u(r,theta,0)=0, u(r,theta,H)= f(r,theta), u(r,0,z)=0, u(r,Pi,z)=0,u(a,theta,z)=0;
sol:=pdsolve([pde,bc],u(r,theta,z)) assuming a>0,r<a,H>0,theta>0,theta<Pi

(diff(u(r, theta, z), r)+r*(diff(diff(u(r, theta, z), r), r))+(diff(diff(u(r, theta, z), theta), theta))/r+r*(diff(diff(u(r, theta, z), z), z)))/r = 0

u(r, theta, 0) = 0, u(r, theta, H) = f(r, theta), u(r, 0, z) = 0, u(r, Pi, z) = 0, u(a, theta, z) = 0

"sol := "

unassign('r,theta,z,f,H');
pde:=VectorCalculus:-Laplacian(u(r,theta,z),'cylindrical'[r,theta,z])=0;
bc:=u(r,theta,0)=0, u(r,theta,H)= 0, u(r,0,z)=0, u(r,Pi,z)=0,u(a,theta,z)=0;
sol:=pdsolve([pde,bc],u(r,theta,z)) assuming a>0,r<a,H>0,theta>0,theta<Pi

(diff(u(r, theta, z), r)+r*(diff(diff(u(r, theta, z), r), r))+(diff(diff(u(r, theta, z), theta), theta))/r+r*(diff(diff(u(r, theta, z), z), z)))/r = 0

u(r, theta, 0) = 0, u(r, theta, H) = 0, u(r, 0, z) = 0, u(r, Pi, z) = 0, u(a, theta, z) = 0

Error, (in assuming) when calling '`PDEAdvisor/2nd_order/Series/ThreeVariables`'. Received: 'invalid input: rhs received _Z3, which is not valid for its 1st argument, expr'

 


 

Download bug3.mw

Dear Maple friends~

Recently I am thinking a question about how to use Maple to prove an equation based on a known partial differential equationand its boundary conditions.

Although I can Prove it with hand computation ,it still has some difficulty and it will be really hard if its partial differential equation become more complex(As a matter of fact, it will happen).So I think of Maple and want to take advantage of computer.However,I get few ideas how to realize it .The details are as follows:

alias(u=u(x,t)):
pde:=diff(u,t)-diff(u,x$2,t)+4*u^2*diff(u,x)=3*u*diff(u,x)*diff(u,x$2)+u^2*diff(u,x$3);
N:=5;#actually N can be any positive integer!
bcs:=eval(u,x=-infinity)=0,seq(eval(diff(u,x$ha),x=-infinity)=0,ha=1..N),eval(u,x=infinity)=0,seq(eval(diff(u,x$ha),x=infinity)=0,ha=1..N);
E:=Int(u^4+2*u^2*diff(u,x)^2-diff(u,x)^4/3,x=-infinity..infinity);

#try to prove the following equation
diff(E,t)=0

The written proof is as follows:

Therfore,I submit such a problem and look forward your solutions and suggestions sincerely~

Hello everyone, Greetings!

I am facing a really strange problem. I need to write an expression, however, maple out of nowhere assigns values to the variable used. only to those which are written inside sin (). In previous versions the out put is fine. Is there a new way to write expressions in maple 2019? I am not sure.


 

restart

96*sin(2*beta*y)*cos(2*beta*y)*beta^4 + 96*sin(2*beta*y)*beta^4

(0.525982730176588e-113+0.525982730176588e-113*I)*beta^4

(1)

``


 

Download strngmpl.mw

 

If I have checked the Editable button just below the working window, then the temperature would be very high in the next time when I start Maple 2019. I do not what is going on. But when I unchecked the Editable button, and wait for several seconds, then the temperature and the load of my laptop are on the normal state.  Is this a bug for Maple 2019? My OS is Debian Stretch, that is,

$ uname -a
Linux debian 4.9.0-9-amd64 #1 SMP Debian 4.9.168-1 (2019-04-12) x86_64 GNU/Linux

 

I was wondering why Maple hangs on this first order heat pde (waited for more than 15 minutes)

pde:= diff(u(x,t),t)= diff(u(x, t), x$2) - 9*diff(u(x,t),x);
bc:=u(0,t)=0,u(1,t)=0;
ic:=u(x, 0) = exp(45/10*x)*(5*sin(Pi*x) + 9*sin(2*Pi*x) + 2*sin(3*Pi*x));
#infolevel[pdsolve]:=3;
pdsolve([pde,ic,bc],u(x,t))

It shows it hangs here:

Trying HINT = _F1(x)*_F2(t)
                           Trying given functional HINT ...
                     Third set of solution methods successful

Mathematica solves this very quickly and returns

heqn = D[u[x, t], t] == D[u[x, t], {x, 2}] - 9*D[u[x, t], x];
ic = u[x, 0] == Exp[45/10 x]*(5 Sin[Pi*x] + 9 Sin[2*Pi*x] + 2 Sin[3*Pi*x]);
bc = {u[0, t] == 0, u[1, t] == 0};
sol = DSolve[{heqn, ic, bc}, u[x, t], {x, t}]

I am asking becuase Maple normally have no problem with such PDE's so I was surprised it hangs on this one and was trying to find out why.

Other than using infolevel[pdsolve]:= what other tools should one try to debug where exactly it hangs and why?

Maple 2019, Physics V 350

Hi,

I am having issues with switching from math mode to text mode, when it comes to adding a new line of text under a line of math mode, without evaluating the math. In a previous version of Maple (not sure witch one, probably Maple 2018), I would switch from math mode to text mode by using the shortcut "command + T", followed by hitting the "->" button on the keyboard and then hit enter to start a new line in text mode. But this does not work in the latest version of maple. Does anyone have a solution for this problem?

Also, is there a way to remove the "toolbox" (i.e. "solve for"/"expand"/"simplify"/"isolate"/etc.), so it only appears when right-clicking on the expression you want to edit?

It's no secret that I liked the older versions of Maple, but I'd very much appreciate some assistance with the 2019 version!

Kind regards,

Lisa

My Maple Worksheets (not Maple Documents) have lots of explanetory Text blocks [..... surounding executable Math blocks ([> ..... I often insert mathematical symbols, most commonly subscripted variables, in these Text blocks.  For a simple example, consider the text block entered as

[This is a test of a subscripted variable "CTL-R" h__0 "CTL-T" in a text block.

The "CTL-R" (quotes are not actually entered) is the short cut to go into math mode, and "CTL-T" exits math mode and returns to text mode and the double underscore produces an atomic subscripted variable.

The text block actually will look like

[This is a test of a subscripted variable h0 in a text block.

The problem occurs when I reexecute the worksheet. The Text block actually produces output labeled with an equation number. For my simple example above the Text block becomes

[This is a test of a subscripted variable h0 in a text block.

[                                              h0                                                   (1)

 

where the two lines started by [ are actually merged with one expanded [ for the Text block with its output. To get rid of the unwanted output, I have to put my curser over the h0 that is in the Text body (not the output h0) and hit "Shift-F5". The output h0 with its equation number disappears.  If there are a number of simple math expressions in a text block, I have to process them one at a time with "Shift-F5". This takes up a lot of time. With earlier Maple versions (~2015 or earlier) I used to fly through Text blocks using the shortcuts "Ctl-R" and "Ctl-T" and these Text blocks produced no output when the worksheet was reexecuted. 

Starting with Maple 2016 I could enter math expressions in Text blocks using the shortcuts, but I could not copy and paste  a Text block with inline math expressions without the expressions becoming "live" in the copied block.  Starting with Maple 2017 all my Text boxes with math expressions began executing the math and producing output.

I gave up on Maple 2017 and 2018.  I have finally made the jump from Maple 2016 to Maple 2019, in part, because I finally discovered the "Shift-F5" trick to make math expressions in a Text block inactive.

Does anyone know how to make the default behaviour of Maple with math expressions in a Text block to be "Don't execute the math and produce output in the Text block"?

I would post an actual example worksheet, except I have never been successful whenever I have tried to upload a worksheet. I hope my description above is adequate.

Any help will be greatly appreciated.  Neill Smith

 

 


 

restart; with(VectorCalculus)

r := `<,>`(sin(t), cos(t), t)

Vector(3, {(1) = 0.2739493386e-115+0.2739493386e-115*I, (2) = 1.0-0.7504824014e-231*I, (3) = t})

(1)

``


what??

Download problem.mw

Earlier smoothly working generation of normal distribution in v. 2019 unexpectedly shows the error:

RandV  := Statistics[RandomVariable](Normal(0, 1));
Statistics[Sample](RandV, 10);

Error, (in p) unable to convert Float(undefined) to an integer

 

I have noticed a few times now with Maple 2019. It looses kernel connection when it is sitting there idly. This time I observed it. Had saved a document after an intensive calculation. The memory used was about 30Gig. shortly after saving the cpu fan was running hard. I checked task manager and cpu was cycling to 100%, it was mserever. Then the memory usage droped to about 6gig and message as shown. During this time Maple screen down in the LH corner displayed "Ready", so it didn't think it was doing anything.
 

Hello,

How I can take variation from left-hand side of  5, and reach to right-hand side of  5. After by using integral by part obtained  7?

Thank you

Maple pdsolve supports periodic boundary conditions. So I was hoping it will be able to solve the heat PDE inside disk with periodic boundary conditions. But I am not able to make it work. 

Is there a trick to make Maple solve this, is there something I need to add or adjust something else? or it is just the functionality is not currently implemented?

This is what I tried

restart;

pde := diff(u(r,theta,t),t)=diff(u(r,theta,t),r$2) + 1/r*diff(u(r,theta,t),r)+1/r^2*diff(u(r,theta,t),theta$2);
bc1 := u(a,theta,t)=0;
bc2 := eval(diff(u(r,theta,t),theta),theta=-Pi)=eval(diff(u(r,theta,t),theta),theta=Pi);
bc3 := u(r,-Pi,t)=u(r,Pi,t);
ic  := u(r,theta,0)=f(r,theta);
sol := pdsolve([pde, bc1,bc2,bc3, ic], u(r, theta, t), HINT = boundedseries(r = 0)) assuming a>0,r>0

I solved this analytically by hand using standard separation of variables method. The issue of telling Maple the solution is bounded at center of disk, I assume is being handled automatically by the HINT=boundedseries(r = 0).

If I remove the hint, it also does not solve it. 

Maple 2019, Physics package 338

For this problem

I'd like to see if Maple can give, or simplify the solution it now gives to look like this solution 

The one it currently gives is

restart;

pde:=diff(w(x,t),t)+c*diff(w(x,t),x)=0; 
ic:=w(x,0)=f(x);
bc:=w(0,t)=h(t);
sol:=pdsolve([pde,ic,bc],w(x,t))  assuming t>0,x>0,c>0

 

And I did not know how to simplify it or obtain the simpler one. I tried strip and TWS hints.  I also do not understand why Maple gives an integral with 0 as upper limit there (the second integral).

Using Physics package cloud version 338 and Maple 2019. On windows 10.

Thank you

1 2 3 4 5 6 7 Last Page 3 of 19