Some special graphs are temporarily difficult to be generated by maple's function NonIsomorphicGraphs. So I want to read some such data from the following URL.

http://users.cecs.anu.edu.au/~bdm/data/graphs.html

But recently I found out that the data on this website has been changed. Different graphs are not on a single line, so I can’t read them by maple effectively. The previous method fails.

https://www.mapleprimes.com/questions/228819-How-To-Import-All-Graphs-In-A-Graph6-File

For example： all 41 Strongly regular graphs(19,14,6,7).The g6 file is converted into text format, as shown below

I don’t know how to select some graphs from them , so helpless.

I have two equations (assignments, to be accurate) from which I know they are equal:

f__1 := sqrt(4*a^2 + lambda__g^2)*c/(2*lambda__g*a)

f__2 := c*sqrt(1/lambda__g^2 + 1/(4*a^2))

However:

testeq(f__1 = f__2) returns FAIL

verify(f__1, f__2, equal) returns  FAIL

and

simplify(f__1 - f__2, sqrt)

does not return 0 but

-c*(sqrt((4*a^2 + lambda__g^2)/(lambda__g^2*a^2))*lambda__g*a - sqrt(4*a^2 + lambda__g^2))/(2*lambda__g*a)

What is the best method for checking such equalities?

I am sorry for not using the Maple Math input option but fpr such reason it did not accept the expressions in this question. I am sure I made a mistake but I do not know what mistake.

I tested all methods mentioned above with the 1. Binominal equation sucessfully.

Hi experts in the field of solving complex system of ODE

I have this sytem of var. are  (n(t),u(t),z(t)) with delta and t are (real)

then want to plot 3d n(t) as a function of( t, delta)

restart:assume(delta,real):
phi:=0:lambda:=0.1:N:=5:M:=sqrt(N*(N+1))*exp(I*phi):omegap:=10:
var:={n(t),u(t),z(t)}:
dsys:={diff(n(t),t)=-2*(n(t)-N)+(u(t)-M)*exp(-2*I*omegap*t/lambda)+((z(t)-conjugate(M))*exp(2*I*omegap*t/lambda)),diff(u(t),t)=-2*(1-I*delta)*u(t)+2*(n(t)-N)*exp(2*I*omegap*t/lambda)+2*M,diff((z(t),t))=-2*(1+I*delta)*z(t)+2*(n(t)-N)*exp(-2*I*omegap*t/lambda)+2*conjugate(M)}:
res1:=dsolve(dsys union {n(0)=0,u(0)=0,z(0)=0},numeric,output=listprocedure);

P3:=plots3d(n(t),t=0..1,delta=-10..10,axes=boxed,tickmarks = [3, 2], color = black, thickness = 1, linestyle = solid, titlefont = [Helvetica, roman, 18], labeldirections = [horizontal, vertical], labelfont = [Helvetica, roman, 24]);

Hi!

How to get the plot of the system of the equation below:

Tau >=0.Plot.mw

I did not succeed.

Thanks

plot3d(abs(Zeta(x + y*I)), x = -4 .. 5, y = -10 .. 40, view = [-4 .. 5, -10 .. 40, 0 .. 4])

Hi, is it possible to stretch y axis to get more satisfyng view of this graph? (without using scaling cosntrained)

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

x0 := x - Pi/4;
y0 := y - Pi/4;
z0 := z - Pi/4;
f := (x, y, z) -> 10*sin(x0)*sin(y0)*sin(z0) + 10*sin(x0)*cos(y0)*cos(z0) + 10*cos(x0)*sin(y0)*cos(z0) + 10*cos(x0)*cos(y0)*sin(z0) - 7/10*cos(4*x) - 7/10*cos(4*y) - 7/10*cos(4*z);
implicitplot3d(evalc(f(x, y, z) = 9), x = -4.5 .. 4.5, y = -4.5 .. 4.5, z = -4.5 .. 4.5, grid = [60, 60, 60], style = patchnogrid);

Hi, do you know how can I restrict this plot using another implicitplot3d let's say sphere given by x^2+y^2+z^2<=4.5?

Look at the following Maple code and output, from Maple 2020. Can you explain the results? I know returning an uninitiated local variable is bad practice, but I cannot make sense of what happens when I do it anyway (just to understand the internals of the Maple language). Should I simply consider the results as undefined behavior?

> f:=proc()                                                                    
>     local x;                                                                 
>     return x;                                                                
> end proc:                                     

> a1 := f() + f();                                                             
                                   a1 := 2 x

> a2 := f() - f();                                                             
                                  a2 := x - x

> a1 + a2;                                                                       
                                  2 x + x - x

> a3 := f() + f() + f();                                                       
                                   a3 := 3 x

> a4 := f() + f() + f() - f();                                                 
                                 a4 := 3 x - x

f := z -> 1 + z/(1 + z^2/(1 + z^3/(1 + z^4/(1 + z^5/(1 + z^6/(1 + z^7))))))

Hi,do you know how to write a loop that would create such a continued fraction?

How to simplify the product of 4x4 matrices and how can we take out the expression that appears in each entry of the matrix?

MLM-1.mw

Hi,

I'm trying to use an older package but the results of the author's own example returns the error:

"Error, (in SumTools:-DefiniteSum:-ClosedForm) summand is singular in the interval of summation"

I don't have access to the source coude, but by looking at other similar issues it seems to be happening when "sum" function is used. Is there a way to force Maple use "add" instead?

Thanks!

What im trying to do is build a 14 faced polyhedron from 9 vertices however when i try to plot 1 of these faces as defined by these vectors using polygonplot3d,


 

the resulting graph plots the points, [17/2,-17/2,0],[0,0,11/2],[0,0,sqrt(166/4)] instead of how they are given by their vectors. It plots correctly if i use "polygonplot3d(Matrix([A1, A2, B1]))" but this does not scale well to my full polyhedron as Im not sure how to choose my faces in that regard. Is there any way I can force polygonplot3d to actually plot the vectors as points properly. Or is it simplist to convert all my vectors to lists first before plotting?

Thanks a lot, Seb
 

Hello there, 

Would you tell me how to treat differentiation as an operator?

Here is a simple example:

(The content of the worksheet is supposed to be here, but that did not work)

Download Q20210407.mw

The 'coeff' operation shows 'psi__d0' as the only coefficient of 'Delta__delta(t)', while what I wanted to see is the 'Desired' expression in the worksheet, '(psi__d0 + psi__q0 / omega__0 * D)' as the coefficients. Here, 'D' represents the differentiation. 

Thank you, 

In Kwon Park 

EssayTools command SpellCorrectWord("trnu") will return "run" and not return "turn".

Is there a way for Maple to only find anagrams with the same length as the given string?

Can Maple do this referencing an external dictionary located on the internet e.g. a complete Websters?