## Spacing between 2D Input and 2D Output cells...

How to change the distance (spacing) between 2D Input cells and 2D Output cells so that this procedure can be inserted into a style sheet and thus applied to multiple documents?

Regards

Oliveira

## How can Maple display an accurate uniform tiling o...

This worksheet creates geodesics in the Poincare disk by transformation of a series of circles of diminishing radii in the complex plane.

The intersections of the geodesics are meant to create the first few pentagonal uniform tilings in the Poincare disk.

I do not know the mathematically correct way to create such a display, so the radii of the circles are only a trial and error approximation.

What Maple code will provide the radii of the complex circles which produce an accurate uniform pentagonal tiling?

Is there a better overall strategy for producing uniform tilings of the Poincare disk?

HyperbolicTiling.mw

## Can an ellipsoid be internally tangent to any tetr...

This worksheet displays an ellipsoid internally tangent to the four sides of a tetrahedron.

The tetrahedron is a special case: it has a horizontal base with vertices A,B and C and its fourth vertex E is on the z axis.

However I have failed when trying to display an internally tangent ellipsoid in any other tetrahedron.

Will any tetrahedron support one or more internally tangent ellipsoids?

If so, are there conditions restricting the location of the mutual points of tangency?

Ellipsoid_in_a_tetrahedron.mw

## Why is the minus sign so weak even in the bold fon...

Why is the minus sign so weak even in the bold font case? My students sometimes miss it in online tests.
How do we make the minus sign bolder?
Thank you!

mapleatha

## Why are my drawing elements misaligned when I prin...

I've noticed after a creating a few documents that when save such documents as PDFs on my Mac, the drawing elements in my drawings are misalgined. Is this just a bug or is there a way to prevent this?  I've attached screenshots of the correct drawign in a document and what the result is in a pdf.

## Unexpected symbols when typing simple operators...

Hello

I have used Maple almost daily for the last four years, but a few days ago two students approached me with an issue I had never encountered before. However, it had happened to both of them within a few weeks.

They described the issue as follows: When they opened a random Maple document and they tried to type in simple operators (like +, - or *), Maple would instead write an odd symbol, which none of them recognised as a mathematical symbol.

As they could not find a way to solve the problem within Maple, they tried restarting their computers. When they afterwards reopened Maple, the problem was gone and the operators worked as expected again. Neither of the students has experienced the issue since.

During the last few days, I have been trying to replicate the issue myself without success. Therefore, I also don't have any screenshots to share, so hopefully my simple explanation is enough.

My questions are: Has anyone heard about this issue before? Does anyone know what might have caused it? Is there a way to replicate it and/or prevent it from happening again in the future?

I hope someone is able to clarify it a bit for me! :)

Regards,

Frederik

## Empty output from pdsolve...

hi, I wonder why this output is empty because I tried to get solution below partial equation:

restart;
with(PDEtools);
pe := diff(u(t, x, y), t) = u(t, x, y) - diff(u(t, x, y), x \$ 2) - diff(u(t, x, y), y \$ 2) + (1 + u(t, x, y)*I)*abs(u(t, x, y))*u(t,x,y)^2;
inc := u(0, x, y) = cos(Pi*x/50) - cos(Pi*x/150)*I;
sys := [pe, inc];

pdsolve(sys);

end after this pdsolve(sys); Maple doesn't show anything

## Why is Maple 2020 in "abcapps.cloud.com" different...

Why is Maple 2020 in "abcapps.cloud.com" different from Maple 2020 in apps.abc.edu? I am connecting to maple 2020 in two different ways to the school where I work. The schools name is, say, "abc". The first version of Maple 2020 has two arrows at the top. The second arrow is the "upload" arrow and allows me to upload a file from my home computer the my folder at school.
The second version of Maple 2020 has no such arrows. Both versions allow me to get my Maple cloud working for local loading and saving Maple files. How can I upload a Maple file to my Maple cloud from my home computer in the second Maple 2020 version in apps.abc.edu? Or, how can I upload a file to my Maple cloud in any way from my home computer?
By the way, the second Maple 2020 version is coming from Microsoft's Remore Desktop Web Client. It look like it has its own navigation bar at the top.

Thank you!

mapleatha

## Maple CodeGeneration exports matrix wrong...

Hello,

I'm using the command

Matlab(AA,resultname="A",optimize=tryhard)

to generate Matlab code for a quite big matrix. The first problem is, that I get a lot of the following warnings

Warning, cannot resolve types, reassigning t33's type

for a bunch of different t** variables. When I copy the generated code to Matlab I get the error: 'Dimensions of arrays being concatenated are not consistent.'

I found that some entries are obviously transposed like

t50 = [0 0 0 0 0 0 t34 0 0 0 0 -t33 t37 0 0 0 0 0 -t44 0 0 0 0 0 t49 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 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];

should be a column vector. Here is a snippet of how the resulting matrix A is constructed (I can't show the full code because it consists of some 100 lines):

A = [t50 t97 t143 t190 t237 t261 ... ]

I tried to manually transpose the entries. The matrix can be generated but the dimension is wrong, hence, it must be a wrong matrix then. Does anyone know what could be the reason for this? I generate the matrix via the Hessian-command

## Is there a more versatile way to draw the curve on...

I read the code in the link below and have some thoughts on drawing the graph.

https://www.mapleprimes.com/questions/216092-Options-For-Graph-Drawing-In-The-GraphTheory

restart:
with(GraphTheory):
with(SpecialGraphs):
G     := PetersenGraph();:
POS := GetVertexPositions(G);
EG   := Edges(G);
PLOT(
seq( CURVES([POS[EG[i][1]], POS[EG[i][2]]], LINESTYLE(3) ), i=1..numelems(Edges(G))),
POINTS(POS, SYMBOL(_SOLIDBOX, 35), COLOR(RGB, 1, 1, 0)),
seq(TEXT(POS[i], i), i=1..numelems(Vertices(G))),
AXESSTYLE(NONE)
)

But if we want to change the edge to a curvilinear style, it seems very difficult. We know  PetersenGraph is 1-planar graph.  The following picture is one of  its 1-plane drawing.  That is  also what I want to draw .

PS: 1-planar graph is a graph that can be drawn in the Euclidean plane in such a way that each edge has at most one crossing point, where it crosses a single additional edge

Although I asked a similar question, but it uses too many special curve functions and the method is relatively isolated. Because the cycle graph is too special.  https://www.mapleprimes.com/questions/228987--Can-We-Draw-Curved-Edges-In-The-Graph

I also noticed the optional items of the edge style.  But there are no curves, such as arcs, parabola, etc.

The plot style must be one of line, point, pointline, polygon (patchnogrid), or polygonoutline (patch).

I am trying to draw a parabola, it seems to be quite difficult. And it completely deviated from the use of graph theory package.

drawarc :=proc(A,B,C,ecolor);

local  c,ax,cx ,ay,cy,ox,oy,oo,x,y,b,a,an_end,an_start,r,yuanhu:
ax :=evalf(geometry)[HorizontalCoord](A):
cx :=evalf(geometry)[HorizontalCoord](C):
ay :=evalf(geometry)[VerticalCoord](A):
cy :=evalf(geometry)[VerticalCoord](C):

geometry[circle](c,[ A ,B ,C], [x,y],'centername' =o):

ox :=evalf(geometry[HorizontalCoord] (o)):
oy :=evalf(geometry[ VerticalCoord] (o)):

if(cx -ox)>0 then
b :=arctan((cy -oy) /(cx -ox)):
elif(cx -ox)=0 and (cy -oy)>0 then

b :=Pi/2 :
elif(cx -ox)=0 and (cy -oy)<0 then

b :=-Pi/ 2 :
else
b :=Pi +arctan((cy -oy) /(cx -ox)):
fi :
if(ax -ox)>0 then
a :=arctan((ay -oy) /(ax -ox)):
elif(ax -ox)=0 and (ay -oy)>0 then

a :=Pi /2 :
elif(ax -ox)=0 and (ay -oy)<0 then

a :=-Pi/ 2 ;
else
a :=Pi +arctan((ay -oy)/ (ax -ox)):
fi ;
if(evalf(b)<evalf(a))then
an_start :=a :
else
an_start :=a +2*Pi :
fi :
an_end :=b :

yuanhu :=plottools[ arc] ([ ox , oy] , r , an_start..an_end):

plots[ display] (yuanhu , scaling =constrained, color =ecolor,axes=none);

end :

geometry[point] (a , -3 .00 , 1 .70);
geometry[point] (b , 0 .35 , -0 .45);
geometry[point] (c , 3 .13 , 1 .86);
l :=[a , b , c] ;
drawarc(a,b,c,blue);

I would like to ask maple if there is a more versatile and simpler way to draw a curve of  graph drawing.

drawarcs:=proc(VL ::list , ecolor , scope);
local i , num , arcs , arc_text , vl , display_set ;
vl :=VL ;
num:=nops(vl);
arcs :={};
i:=1;
if num <3 then
"There isn' t enough points in the point list." ;
return ;
elif irem(num-1 , 2)<>0 then
"The number of the list must be multiple of 2 when it minus 1 .";
fi :
while i <num do
arcs :={drawarc(vl[i] ,vl[i +1] , vl[i +2],ecolor),op(arcs)};
i:=i +2 ;
od ;
arc_text :=geometry[ draw] ({vl[1] , vl[num] }, printtext =true , color =ecolor);
display_set:={op(arcs),arc_text};
plots[ display] (display_set , view =[ -abs(scope)..abs(scope), -abs(scope)..abs(scope)] , scaling =constrained,axes=none);
end proc:
geometry[ point] (v1 , 0 ,0):
geometry[ point] (a , 3, 9):
geometry[ point] (b , 7, 9):
geometry[ point] (c, 6,8):
geometry[ point] (d , 12,9):
geometry[ point] (e , 7 ,2):
geometry[ point] (v3 , 9 ,0):
vl:=[ v1,a,b,c,d,e,v3] :
drawarcs(vl,red,20);

try.mwtry.mw

The above program is too cumbersome and not robust

macro(GS=GetVertexPositions):
with(GraphTheory):
with(SpecialGraphs):
G     := PetersenGraph():
POS := GetVertexPositions(G):
EG   := Edges(G) minus {{6,10},{6,7}}:
s1:=PLOT(
seq( CURVES([POS[EG[i][1]], POS[EG[i][2]]], LINESTYLE(3) ), i=1..numelems(Edges(G))-2),
POINTS(POS, SYMBOL(_SOLIDBOX, 35), COLOR(RGB, 1, 1, 0)),
seq(TEXT(POS[i], i), i=1..numelems(Vertices(G))),
AXESSTYLE(NONE)
):
geometry[ point] (a,op(GS(G)[6])):
geometry[ point] (b , op(GS(G)[7])):
geometry[ point] (c , op(GS(G)[10])):
geometry[ point] (d ,op(GS(G)[8])[1]+0.3,op(GS(G)[8])[2]-0.5):
geometry[ point] (d2 ,op(GS(G)[9])[1]-0.3,op(GS(G)[9])[2]-0.5):
s2:=drawarc(a,d,b,red):
s3:=drawarc(c,d2,a,red):
plots:-display({s1,s2,s3});

## System of PDE's...

PDE:

(a+b)*(uxx+vxy)+c*laplacian(u)=0

(a+b)*(vxy+vyy)+c*laplacian(v)=0

a,b,c=const.  Initial:u=1/2*sin(2*theta),v=cos(theta)

Text book says: Solve by complex variable method

## Grid computing toolbox on local multi-core server...

Is possible to operate Grid Computing Toolbox together with Maple on one local multicore machine?

If yes, what is the proper instalation/configuration procedure on Windows or Linux?

## Second order slope field...

Hey

Is it possible to draw a slope field for a second order differential equation with initial conditions?

## .eps figures produced by Maple are often excessive...

Why 3D .eps figures produced by Maple 2020 are often excessively large?

So, it´s a little heavy to the viewer and to compile to PDF.

• How could we reduce the size without losing any quality?

## how to get types to show up in command completion?...

command completion (when hitting the ESC key) in Maple could be made more useful. It does not seem to support type names for example.

What shows up on the command completion window are  possible commands that start with that partial text.

It does not list other known names by Maple, such as type names and other options.

This makes it hard to use in many places, where one have to remember type names exactly instead of the system helping them by listing all possible type names that start with that string.

Is there a way around this? Will Maple next version support smarter and more complete command completion menu?

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