Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

Is there any setting that controls the extent of a plot?

Left hand plot has defined extent of the plot, while the plot on the right hand side has not. When panning the graphics on the right side the plot is clipped.

Any idea how to make Maple to use the whole extent of the plot component as a boundary?

Download plotpoint2.mw

restart;
with(plots);
with(plottools);
with(DEtools);
N := S(t) + In(t) + C(t);
                    N := S(t) + In(t) + C(t)

eqn1 := diff*(S(t), t) = lambda - (lambda + sigma)*S(t) - (beta + Zeta)*S(t)*In(t) - beta[1]*S(t)*C(t), S(0) = ic1;
 eqn1 := diff (S(t), t) = lambda - (lambda + sigma) S(t)

    - (beta + Zeta) S(t) In(t) - beta[1] S(t) C(t), S(0) = ic1


eqn2 := diff*(In(t), t) = beta*S(t)*In(t) - (lambda + gamma)*In(t), In(0) = ic2;
 eqn2 := 

   diff (In(t), t) = beta S(t) In(t) - (lambda + gamma) In(t), 

   In(0) = ic2


eqn3 := diff*(C(t), t) = Zeta*In(t) + Zeta*In(t)^2 - (rho + lambda)*C(t) - Zeta*C(t)*In(t), C(0) = ic3;
                                                     2
     eqn3 := diff (C(t), t) = Zeta In(t) + Zeta In(t) 

        - (rho + lambda) C(t) - Zeta C(t) In(t), C(0) = ic3


lambda := 0.117852;
                       lambda := 0.117852

mu := 0.035378;
                         mu := 0.035378

beta := 0.11;
                          beta := 0.11

beta__1 := 0.05;
                        beta__1 := 0.05

g := 1;
rho := 0.1;
                           rho := 0.1

zeta := 0.02;
                          zeta := 0.02

sigma := 0.066;
                         sigma := 0.066


ic1 := 2390000;
ic2 := 753;
ic4 := 358500;
                         ic1 := 2390000

                           ic2 := 753

                         ic4 := 358500

dsol := dsolve([eqn1, eqn2, eqn3], numeric);
Error, (in dsolve/numeric/process_input) system must be entered as a set/list of expressions/equations
 

Hi all, how to get radical of expression?

Example: sqrt(a*(a+b+c))/(a*b+a*c+b*c) is 2, (a*b+a*c+b*c)*((1/3)*a+(1/3)*b+(1/3)*c)^(1/3) is 3

Thanks

I have this tedious looking function that I want to write in terms of the other expression but the command i usually use does not work here because the expressions are not polynomials. I am wondering if there is an alternative to doing this manually.
Temp.mw

As an example, the second display in the web site below shows the 42 possible triangulations of a cyclic heptagon polygon.

https://en.wikipedia.org/wiki/Polygon_triangulation

I have a document with quite a few symbols saved to my favorites palette. When I close the file and then reopoen it the Favorites Palette has not changed-the symbols are right where I want them. However, if I open the file with another computer the Favorites Palette is empty! What is happening?  (The document is stored in Dropbox and both computers are Macs running Maple 2023.)

Say I have a data matrix with one dependent variable and 50 independent variable

The first column is the dependent variable columns my first row has header names of variables say.

Is their way to code such that I can do a Linear regression stepwise such that even interactions terms can be into account and check for a best fit.

As only matlab can do it easily as i  see and it is paid costly software.

If pssible any help kind help. 

If possible some code can be written in maple kind help.

I have some large systems of linear equations.  The solutions are probability generating functions.  I can get solutions in a few minutes for systems of up to n= 200 eqns or so, but Maple just cycles indefinitely if I try to solve much larger systems.  I really only need to perform Gaussian Elimination, as I only need to solve for one of the n solutions.  The matrices are sparse, there are only 3 non-zero entries per row.  I tried to get help from the manuals but I get the impression that sparse solutions are only available for numeric computations.   Doesn't Maple allow for sparse symbolic solutions?  If so, how to do it?

What is the correct way to plot objects which have been created by the geometry library.

e.g. circle, point, line, e.g.

restart; with(geometry)

point(B, 2, 0)

B

(1)

form(B)

point2d

(2)

coordinates(B)

[2, 0]

(3)

with(plots)

display(pointplot(B))

Error, (in plots:-pointplot) points are not in the correct format

 

NULL

Download plotpoint.mw

Hi everyone
how can i overcome this error to solve this ODE ? tnx in advanced.

restart

U := 1:L := 10:k := 1:Dea := 0.00001:CA0 := 10:Pe := U*L/Dea:Da := k*CA0^2/Dea:

Eq1 := diff(CA(x), x, x) - Pe*diff(CA(x), x)/L = Da*L*CA(x)^2/CA0;

diff(diff(CA(x), x), x)-100000.0000*(diff(CA(x), x)) = 10000000.00*CA(x)^2

(1)

BCs := CA(0) = CA0, D(CA)(L) = 0

CA(0) = 10, (D(CA))(10) = 0

(2)

ans := dsolve([Eq1, BCs], numeric);

Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging

 

 

Download Hw.mw

Hallo every body 

i have a question How can be written this system of eqautions without the variable "t"

thanks 

restart

``

eq10 := epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))-Y(t)*alpha

epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))-Y(t)*alpha

(1)

eq11 := alpha*X(t)

alpha*X(t)

(2)

eq12 := epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))-beta*U(t)

epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))-beta*U(t)

(3)

eq13 := beta*Z(t)

beta*Z(t)

(4)

eq14 := epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))-W(t)

epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))-W(t)

(5)

eq15 := V(t)

V(t)

(6)

eq16 := epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))

epsilon*F(-(V(t)*alpha^4*beta^2-V(t)*alpha^2*beta^4-S(t)*alpha^4*beta^2+S(t)*alpha^2*beta^4+X(t)*beta^4-Z(t)*alpha^4+S(t)*alpha^4-S(t)*beta^4-X(t)*beta^2+Z(t)*alpha^2-S(t)*alpha^2+S(t)*beta^2)/(alpha^2*(alpha^2-1)*(alpha^2-beta^2)*beta^2*(beta^2-1)), (W(t)*alpha^3*beta-W(t)*alpha*beta^3+Y(t)*beta^3-U(t)*alpha^3-Y(t)*beta+U(t)*alpha)/((alpha^2*beta^2-alpha^2-beta^2+1)*beta*alpha*(alpha^2-beta^2)), (X(t)*beta^2-Z(t)*alpha^2+V(t)*alpha^2-V(t)*beta^2-X(t)+Z(t))/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), -(Y(t)*alpha*beta^2-U(t)*alpha^2*beta+W(t)*alpha^2-W(t)*beta^2-Y(t)*alpha+beta*U(t))/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), -(X(t)*alpha^2*beta^2-Z(t)*alpha^2*beta^2-X(t)*alpha^2+beta^2*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)), (Y(t)*alpha^3*beta^2-U(t)*alpha^2*beta^3-Y(t)*alpha^3+beta^3*U(t)+W(t)*alpha^2-W(t)*beta^2)/((alpha^2-beta^2)*(alpha^2*beta^2-alpha^2-beta^2+1)), (X(t)*alpha^4*beta^2-Z(t)*alpha^2*beta^4-X(t)*alpha^4+beta^4*Z(t)+V(t)*alpha^2-V(t)*beta^2)/((alpha^2-beta^2)*(beta^2-1)*(alpha^2-1)))

(7)

``

Download problem.mw

how can be solved this system in maple 18

restart

fa[1] := -(1/4608)*V[0]^2+(1/4608)*W[0]^2+(1/2304)*U[0]*W[0]+(1/2304)*V[0]*Z[0]``

-(1/4608)*V[0]^2+(1/4608)*W[0]^2+(1/2304)*U[0]*W[0]+(1/2304)*V[0]*Z[0]

(1)

fa[2] := (1/153600)*(45*U[0]^2*V[0]-50*U[0]*V[0]*W[0]-50*U[0]*W[0]*Z[0]-5*V[0]*Z[0]^2-16*Z[0]*r[0]^2)/r[0]

(1/153600)*(45*U[0]^2*V[0]-50*U[0]*V[0]*W[0]-50*U[0]*W[0]*Z[0]-5*V[0]*Z[0]^2-16*Z[0]*r[0]^2)/r[0]

(2)

fa[3] := -(1/153600)*(5*U[0]^2*W[0]+50*U[0]*V[0]*Z[0]-16*U[0]*r[0]^2-50*V[0]*W[0]*Z[0]-45*W[0]*Z[0]^2)/r[0]

-(1/153600)*(5*U[0]^2*W[0]+50*U[0]*V[0]*Z[0]-16*U[0]*r[0]^2-50*V[0]*W[0]*Z[0]-45*W[0]*Z[0]^2)/r[0]

(3)

fa[4] := (1/115200)*(25*U[0]*V[0]*W[0]-25*V[0]*W[0]^2-160*V[0]*r[0]^2-25*W[0]^2*Z[0]-64*Z[0]*r[0]^2)/r[0]

(1/115200)*(25*U[0]*V[0]*W[0]-25*V[0]*W[0]^2-160*V[0]*r[0]^2-25*W[0]^2*Z[0]-64*Z[0]*r[0]^2)/r[0]

(4)

fa[5] := -(1/115200)*(25*U[0]*V[0]^2+64*U[0]*r[0]^2-25*V[0]^2*W[0]-25*V[0]*W[0]*Z[0]-160*W[0]*r[0]^2)/r[0]

-(1/115200)*(25*U[0]*V[0]^2+64*U[0]*r[0]^2-25*V[0]^2*W[0]-25*V[0]*W[0]*Z[0]-160*W[0]*r[0]^2)/r[0]

(5)

``

fa[6] := (11/57600)*U[0]^2+(1/768)*V[0]^2+(1/768)*W[0]^2+(11/57600)*Z[0]^2+(1/600)*r[0]^2

(11/57600)*U[0]^2+(1/768)*V[0]^2+(1/768)*W[0]^2+(11/57600)*Z[0]^2+(1/600)*r[0]^2

(6)

``

``

Download system.mw

Hi!

I want to implement to attached fortran program in Maple 2015 (the procudure starts at the end of the first page). 

localmin.pdf

The code does not seem dificult, but I don't know how to interpret the instructions "go to" of fortran. Reading Maple's doc about the "goto" instruction, I don't understand how to implement it.

Can somebody help with this code, please?

Many thanks in advance for your comments.

An interval graph is an undirected graph formed from a set of intervals on the real line, with a vertex for each interval and an edge between vertices whose intervals intersect. Recognizing interval graphs  is in linear time. 

Seven intervals on the real line and the corresponding seven-vertex interval graph.

 

 

IsIntervalGraph(G) (was introduced in Maple 2022) tests whether the graph G could be expressed as an interval graph for some collection of intervals. If a graph is an interval graph, then the intervals corresponding to its vertices should be given. However,  IsIntervalGraphdoes not provide such an option, which makes it impossible for me to verify the correctness of the results or see more information.

with(GraphTheory):
G:=Graph({{1,2},{1,3},{1,4}, {4,2},{4,3}});
IsIntervalGraph(G)

true

Therefore, an option like the "certificate" option in SageMath needs to be provided.

g = Graph({1: [2, 3, 4], 4: [2, 3]})
g.show()
g.is_interval()
g.is_interval(certificate=True)

(True, {1: (0, 5), 2: (4, 6), 3: (1, 3), 4: (2, 7)})

 

 

I have looked at the source code of IsIntervalGraphand it seems to be checking whether the complement graph is comparability. I am not sure if this transformation can still find the corresponding intervals.

print(IsIntervalGraph)
proc(G::GRAPHLN)::truefalse;
    local G2;
    G2 := GraphTheory:-GraphComplement(G);
    return GraphTheory:-IsComparabilityGraph(G2);
end proc

print(IsComparabilityGraph)
proc (G::GRAPHLN, { transitiveorientation::truefalse := false, 

   usecached::truefalseFAIL := FAIL }, ` $`)::truefalse; local 

   iscomparability, L, A, result, V; A := op(4, G); result := 

   FindTransitiveOrientation(A, transitiveorientation); if 

   result = NULL then false elif transitiveorientation then V 

   := op(3, G); true, GraphTheory:-Graph(V, result) else true 

   end if end proc

 

By the way, can the  "FindTransitiveOrientation "  in the function IsComparabilityGraph be used by the user?

Hello, 
I have an simple exmple of expresion : 

restart;
v1 := sin(c)*sin(a)(a - b);
                  v1 := sin(a)(-b + a) sin(c)

v2 := sin(c1)*sin(a1)(-a + b);
                 v2 := sin(a1)(-a + b) sin(c1)

sort(v1);
                      sin(c) sin(a)(a - b)

sort(v2);
                    sin(c1) sin(a1)(-a + b)


what i want  is :  sort(v2); --->     sin(c1) sin(a1)(b-a)

That mean i want the "+" sign comme alwase first

Merci

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