Maple 2020 Questions and Posts

These are Posts and Questions associated with the product, Maple 2020

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 font case? My students sometimes miss it in online tests.
How do we make the minus sign bolder?
Thank you!

mapleatha

 

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.

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

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

thanks in advance

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

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

 

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 :

r :=geometry[ radius] (c); 
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});

 

 

 

 

 

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

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?

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? 

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?

 

 

Hi,

I was hoping to run two procs: tgf3 and tgf4 in parallel using Grid, Run and get a faster execution time. As I understood the description of Grid Run, the first call to Grid Run will run in the background and before it is finished the second call Grid Run will start. I do not believe I have that situation in my script. I am not understanding Grid Run. How can this problem be fixed? Here is just a portion of the script using Grid Run:

Use Grid Run 0 for tgf3 and 1 for tgf4. Determine the real time and compare times. The Grid Runs do not appear to run in parallel.

rgt := time[real]();
Grid:-Run(0, `~`[tgf3@op](convert(L, listlist)), 'assignto' = ans3roots);
Grid:-Run(1, `~`[tgf4@op](convert(L, listlist)), 'assignto' = ans4roots);
ans3roots;
ans4roots;

GridRunTime := time[real]() - rgt;
                     GridRunTime := 44.074

Here is my script:

Grid_Run_2.mw

 

Thank you for your help.

I have created a set of help files using the example templates. After I create the .help file and install it with my package, I can view the help pages in the help viewer. However, when I click on any link within a help page, the target page opens as a worksheet in Maple. I understand this is because I created the hyperlink with a worksheet as the target. However, I don't know where to obtain the help topic name for a help page before it has been created.  I have searched help, but can't find any applicable guidance.  Can anyone tell me how to determine the help topic name when first creating the help pages.

I have attached one of my help file worksheets.     Hlpdiracmatrices.mw

Hello,

When I create a vector in spherical coordinates and map it to cartesian coordinates with Physics[Vectors] package as follows,

restart:with(Physics[Vectors]):
q_:=a _r + b _theta + c _phi
ChangeBasis(q_,cartesian)

I get the answer:

(a*cos(phi)*sin(theta)+b*cos(phi)*cos(theta)-c*sin(phi)) i + (a*sin(theta)*sin(phi)+b*cos(theta)*sin(phi)+c*cos(phi)) j + (-b*sin(theta)+a*cos(theta)) k

which is what I would expect.

But if I try to do that with VectorCalculus package as follows,

q := SetCoordinates(<a, b, c>, spherical)
MapToBasis(q, cartesian)

This gives 

(a*sin(b)*cos(c)) ex + (a*sin(b)*sin(c)) ey + (a*cos(b)) ez

I am confused about this!

The SetCoordinates(<a, b, c>, spherical) command outputs

q:=(a) er  + (b) ephi + (c) etheta

here, a,b, and c are  depicted as the components of the vector q in spherical coordinates, but when I map to cartesian coordinates, a,b, and c are treated as if they were the coordinates in spherical coordinates rather than components-- unlike ChangeBasis in Physics[Vectors] package.

Why are these two different?

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