MaplePrimes Questions

Hi everyone, I am trying to draw bar graph for my expression, but received error. Could anyone please help me in this regard.

Help_Bar_graph.mw

Hi

On the latest Maple 2022 version, using dsolve with 1st order ODE and Dirac function returns an incorrect solution

dsolve({D(y)(t) + y(t)/tau = Dirac(t)/tau, y(0) = 0})

See attached image. The correct impulse response should be :

y(t) = exp(-t/tau)*Heaviside(t)/tau

The returned solution is 0 for t = 0 and scaled by a 1/2 for t > 0. I never had such an issue with older Maple versions. Is this a bug or am I doing something wrong

Here is the expected solution followed by the Maple solution:

Hi,

I use the RamdonGraph function quite a bit and wanted to know if it is possible to generate random graphs with specific properties, beyond the typical order, size, connectednes, etc. Specifically, I am interesting in generating eulerian (containing an eulerian circuit), semi-eulerian (containing an eulerian trail) and hamiltonian (containing a spanning cycle)  graphs. Also, the abiltiy to randomly generate graphs that have none of these properties would be helpful.

How do I find the contents of a bin in a Maple histogram?

hello,

I computed some algebraic calculation, but near point -1 there is some issue like disconvergencies. Can anyone help in this regard? In the final graph, as seen the paths of the curves are close together and convergence does not occur AROUND POINT -1.

restart

Digite := 30

30

(1)

beta := 2.5; lambda := 0.1e-1; b := Pi; a := Pi; alpha := 0; y[1] := 1.5; y[2] := 1.5; x[1] := -1; x[2] := 1; Q[1] := 40; Q[2] := 35; T[1] := 20

2.5

 

0.1e-1

 

Pi

 

Pi

 

0

 

1.5

 

1.5

 

-1

 

1

 

40

 

35

(2)

v := (2*n-1)*Pi/(2*b)

Delta := exp(2*v*a)*(alpha*v+beta)*(1+lambda)-(1-lambda)*(alpha*v-beta)

omega := Pi/(2*b)

P[1] := ((1+lambda)*exp(-v*abs(x-xi))+(1-lambda)*exp(v*(x+xi)))*exp(2*v*a)+(1+lambda)*exp(-v*(x+xi))+(1-lambda)*exp(v*abs(x-xi))

P[2] := ((1+lambda)*exp(-v*abs(x-xi))+(1-lambda)*exp(v*(x+xi)))*exp(2*v*a)-(1+lambda)*exp(-v*(x+xi))-(1-lambda)*exp(v*abs(x-xi))

P[3] := P[1]*(-alpha^2*v-alpha*beta+alpha*v)+beta*P[2]

G[11] := (sum((alpha*P[1]*(1-lambda)*(alpha*v-beta)*exp(-2*v*a)+(1+lambda)*P[3])*(cos(v*(y-eta))-cos(v*(y+eta)))/(v*(exp(2*v*a)*(alpha*v+beta)*(1+lambda)-(1-lambda)*(alpha*v-beta))), n = 1 .. 80))/(2*b*(1+lambda))+(2*(1+lambda)*alpha*b/Pi*.25)*ln((1+2*exp(-omega*abs(x-xi))*cos(omega*(y-eta))+exp(-2*omega*abs(x-xi)))*(1-2*exp(-omega*abs(x-xi))*cos(omega*(y+eta))+exp(-2*omega*abs(x-xi)))*(1+2*exp(-omega*(2*a+x+xi))*cos(omega*(y-eta))+exp(-2*omega*(2*a+x+xi)))*(1-2*exp(-omega*(2*a+x+xi))*cos(omega*(y+eta))+exp(-2*omega*(2*a+x+xi)))/((1-2*exp(-omega*abs(x-xi))*cos(omega*(y-eta))+exp(-2*omega*abs(x-xi)))*(1+2*exp(-omega*abs(x-xi))*cos(omega*(y+eta))+exp(-2*omega*abs(x-xi)))*(1-2*exp(-omega*(2*a+x+xi))*cos(omega*(y-eta))+exp(-2*omega*(2*a+x+xi)))*(1+2*exp(-omega*(2*a+x+xi))*cos(omega*(y+eta))+exp(-2*omega*(2*a+x+xi)))))/(2*b*(1+lambda))+(2*(1-lambda)*alpha*b/Pi*.25)*ln((1+2*exp(omega*(x+xi))*cos(omega*(y-eta))+exp(2*omega*(x+xi)))*(1-2*exp(omega*(x+xi))*cos(omega*(y+eta))+exp(2*omega*(x+xi)))*(1+2*exp(-omega*(2*a-abs(x-xi)))*cos(omega*(y-eta))+exp(-2*omega*(2*a-abs(x-xi))))*(1-2*exp(-omega*(2*a-abs(x-xi)))*cos(omega*(y+eta))+exp(-2*omega*(2*a-abs(x-xi))))/((1-2*exp(omega*(x+xi))*cos(omega*(y-eta))+exp(2*omega*(x+xi)))*(1+2*exp(omega*(x+xi))*cos(omega*(y+eta))+exp(2*omega*(x+xi)))*(1-2*exp(-omega*(2*a-abs(x-xi)))*cos(omega*(y-eta))+exp(-2*omega*(2*a-abs(x-xi))))*(1+2*exp(-omega*(2*a-abs(x-xi)))*cos(omega*(y+eta))+exp(-2*omega*(2*a-abs(x-xi))))))/(2*b*(1+lambda))

g[12] := lambda*((alpha*v+beta)*exp(v*(2*a+x))+(alpha*v-beta)*exp(-v*x))*exp(-v*xi)/(v*Delta)

G[12] := (sum(g[12]*(cos(v*(y-eta))-cos(v*(y+eta))), n = 1 .. 80))/b

phi[1] := int(int(G[11]*Q[1]*Dirac(xi-x[1])*Dirac(eta-y[1]), xi = -a .. 0), eta = 0 .. b)+int(int(G[12]*Q[2]*Dirac(xi-x[2])*Dirac(eta-y[2]), xi = 0 .. infinity), eta = 0 .. b)

Z[1] := diff(phi[1], x)

psi[1] := int(Z[1], y)

plot3d(psi[1], x = -a .. 0, y = 0 .. b)

 

with(plots)

contourplot(psi[1], x = -a .. 0, y = 0 .. b)

 

 

Download sai_1.mw

I have a guess about the set of the zeros of the following polynomial

y(1-x^{m+1}z)+(1-x^{n+1}z), (here m,n are positive integers and z is a primitive d-root of unity)

which are located on the complex 2-dimensional torus. The set of solutions is finite (I think the system is zero-dimensional). My goal is to verify my guess numerically using Maple for some small values of m and n and a fixed value of z. I think if (x,y) is a solution, then x is either a (n-m) root of unity or a (n-m) root of 1/z^2 (where n>m).

You can find my code for n=3 and m = 1 attached (I was not able to load the mw format so I put the zip version). I consider z to be a third root of unity but actually, I am interested in putting z= exp(2pi/3*i) and even the real third root z=1 is not interesting for me, but since the exponential representation led to an error, I changed it to z and mentioned that z^3=1. Still, it has an error and  I would be grateful if you could let me know how I can correct this code.  

Question.maple.zip

what the meaning this warning : Warning, cannot evaluate the solution further right of 1.3344882, probably a singularity

how to analize this warning
Thank you

How do I format the display of numbers in Microsoft Excel 365 using the Maple 2023 Add-In?

The default formatting is inconsistent: displays as but displays as . At minimum, I would like all of the numbers to display using a consistent format, preferably standard scientific notation (1.27420168E7 and not or ).

Hi,
I wanted to do a 3d plot such that a function is plotted over a polar plane. I am not sure what is the best way to plot this and would appreciate some guidance/tips.

I want to plot the following function 1/(r^2*sin(theta)^2) .

I tried plot3d but the base plane is not a circle but a square...

Hello!

I have a i9 9th Generation processor with 32 GB ram

If I upgrade to a i9 13 Generation processor with 64 GB ram

Assume I change the main card to Z790

I wonder if I will notice a big improvement in performance when running Maple 2023?

Kjell

I have been writing a language translator. I have everything working reasonably well except that when translating abs(expr) with optimize=tryhard, the IntermediateCode converts the abs() into if...then...else statements. This would be fine except the type of the expr is generally a complex number. I need to optimize the code because there is a lot of redundant calculations otherwise.

I can't figure out how to get IntermediateCode from breaking the abs function into if...then...else statements. [My solution so far is to substitute abs with a dummy name and then use the translator to translate the dummy name into an abs statement - That's really not how things should work!]

Any suggestions?

I've included some example test cases of what is going wrong.

with(CodeGeneration)

testproc1 := proc (x) abs(x) end proc

IntermediateCode(testproc1, optimize = tryhard)

Scope( nametab,
  AssignedName(Name("testproc1"), Scope( nametab,
    Procedure(
      ParameterSequence(Declaration(Name("x"), Type(integer))),
      LocalSequence(Declaration(Name("s1"), Type(integer))),
      OptionSequence(),
      ExpressionSequence(),
      StatementSequence(
        If(
          ConditionalPair(LessEqual(Integer(0), Name("x")), StatementSequence(
            Assignment(Name("s1"), Name("x"))
          )),
          ConditionalPair(Less(Name("x"), Integer(0)), StatementSequence(
            Assignment(Name("s1"), Negation(Name("x")))
          )),
          StatementSequence(
            Assignment(Name("s1"), Integer(0))
          )
        ),
        Return(Name("s1"))
      ),
      DescriptionSequence(),
      GlobalSequence(),
      LexicalSequence(),
      Type(integer)
    )
  ))
)

 

testproc2 := proc (x::numeric) abs(x) end proc

IntermediateCode(testproc2, optimize = tryhard)

Scope( nametab,
  AssignedName(Name("testproc2"), Scope( nametab,
    Procedure(
      ParameterSequence(Declaration(Name("x"), Type(numeric))),
      LocalSequence(Declaration(Name("s1"), Type(numeric))),
      OptionSequence(),
      ExpressionSequence(),
      StatementSequence(
        If(
          ConditionalPair(LessEqual(Float(0, 0), Name("x")), StatementSequence(
            Assignment(Name("s1"), Name("x"))
          )),
          ConditionalPair(Less(Name("x"), Float(0, 0)), StatementSequence(
            Assignment(Name("s1"), Negation(Name("x")))
          )),
          StatementSequence(
            Assignment(Name("s1"), Float(0, 0))
          )
        ),
        Return(Name("s1"))
      ),
      DescriptionSequence(),
      GlobalSequence(),
      LexicalSequence(),
      Type(numeric)
    )
  ))
)

 

NULL

testproc3 := proc (x::complex) abs(x) end proc

IntermediateCode(testproc3, optimize = tryhard)

Scope( nametab,
  AssignedName(Name("testproc3"), Scope( nametab,
    Procedure(
      ParameterSequence(Declaration(Name("x"), Type(complex))),
      LocalSequence(),
      OptionSequence(),
      ExpressionSequence(),
      StatementSequence(
        Return(FunctionCall(Name("abs"), ExpressionSequence(Name("x")), unknown))
      ),
      DescriptionSequence(),
      GlobalSequence(),
      LexicalSequence(),
      Type(numeric)
    )
  ))
)

 

NULL

Download intermediate_code_abs.mw

I'm using NLPSolve to minimize a complicated function. It works great, but the answers are not returned in numerical form which I need as they are then input for the next stage of my program.

How to I extract numbers?

S2 := NLPSolve(test, phi1 = 0 .. 2*Pi, phi2 = 1.0*Pi .. 2*Pi);
     S2 := [-1.00000000011810774, 

       [phi1 = 0.773215730257661, phi2 = 5.98741001513872]]
==>The Result is a list and the solutions appear kind of string-like. 

S2[2,1] returns 'phi=0.773...' not the number I need

Dear all 

I have a system of  second order difference equation.

How, can I update the iterate solution and solve the system

System_of_equations.mw

Thank you

Dear all
I would like to verify if the proposed solution u_exact of my partial differential equation defined on \mathbb{R}^2, with zero boundary condition 
I write the  exact solution, how substitute this  to verify that the PDE is satisfied or not. I tried to substitute but I think someting missing. 
Please check ...

solution_pde_check.mwsolution_pde_check.mw

Thank you

restart:

  ra:=2: b1:=1.41: na:=0.7: we:=0.5: eta[1]:=4*0.1: d:=0.5:
  xi:=0.1: m:=na: ea:=0.5: pr:=21: gr:=0.1: R:=0.9323556933:

  PDE1:=ra*(diff(f(x,t),t))=+b1*(1+ea*cos(t))+(1/(R^2))*((diff(f(x,t),x,x))+(1/x)*diff(f(x,t),x));
  IBC:= {D[1](f)(0,t)=0,f(1,t)=0,f(x,0)=0};

2*(diff(f(x, t), t)) = 1.41+.705*cos(t)+1.150367877*(diff(diff(f(x, t), x), x))+1.150367877*(diff(f(x, t), x))/x

 

{f(1, t) = 0, f(x, 0) = 0, (D[1](f))(0, t) = 0}

(1)

sol := pdsolve({PDE1}, IBC, numeric); sol:-plot(f(x, t), t = 1.2, linestyle = "solid", title = "Velocity Profile", labels = ["r", "f"])

 

``

Download pde.mw

for different time plot of f(x,t) in single plot with different color 

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