Maple 2018 Questions and Posts

These are Posts and Questions associated with the product, Maple 2018

I'd like to view the Maple source code in .maple file. I am not able to find how to do this.

I tried commands in 136697-Can-One-Get-The-Source-Code-Back-From

which applies to .mla using the march command. But it did not work for .maple. It gives an error when trying it on .maple file.

I can open the .maple file in the Maple user interface OK using File->Open

but other than documentation, I see no Maple code.

I am looking now at Physics updates file, which can be downloaded as .maple file from 

https://maple.cloud/app/5137472255164416

Since most Maple code can be viewed, I assume one can also view the source code in the above.

Any idea how to do this?

trying some examples from 209970-Exact-Solutions-For-PDE-And-Boundary--Initial-Conditions-2018

I noticed some answer change when adding assumptions which should not really cause the answer to change. Numerically, both answers seem to be the same. But one is series solution and the other with assumptions added uses integrals.

In wave pde on string where left end at x=0 and adding assumptions x>0,t>0 to pdsolve should produce the same form and it does on some problems but no on others.

Compare

#example 19, wave pde, on string left end fixed, right end moving, with source, no initial velocity
restart;
pde := diff(u(x, t), t$2) = 4*diff(u(x, t), x$2)+(1+t)*x;
bc := u(0,t)=0,u(Pi,t)=sin(t);
ic := u(x,0)=0,eval(diff(u(x,t),t),t=0)=0;

sol:=pdsolve([pde, bc,ic],u(x,t));  #1
sol:=pdsolve([pde, bc,ic],u(x,t)) assuming t>0; #2
sol:=pdsolve([pde, bc,ic],u(x,t)) assuming x>0; #3
sol:=pdsolve([pde, bc,ic],u(x,t)) assuming t>0,x>0;  #4

(1,2,3) above give same answer which is 

but (4) gives

Tried random points and numerically they are the same (set the sum to n=100 to evaluate).

my question is why would adding no assuming, or adding t>0 on its own or adding x>0 on its own give same answer, but adding  t>0,x>0 at same time give such a different looking soution.

I typically adding such assumptions to be safe, but here it seems to had some side effect I have not noticed before.

Physics:-Version();
 "C:\Maple_updates\Physics+Updates.maple", 2018, December 22, 

    10:41 hours, version in the MapleCloud: 265, version installed in this computer: not installed

kernelopts(version)
  Maple 2018.2, X86 64 WINDOWS, Nov 16 2018, Build ID 1362973

 

I try to solve ODE with conditions, but it give answer only without conditions:

SOT.mw

Thank you.

Dear authors,
How to solve this ode problem.

Download link ode.mw

In this problem the boundary condition is

Note: F=g in our problem.

eta approaches N.

Thank you.

 

Executing the entire worksheet several times I obtain random results for Threads:-Seq

restart;

N:=10^3;
f:= (a,b) -> add(evalf(j), j=a..b);

1000

 

proc (a, b) options operator, arrow; add(evalf(j), j = a .. b) end proc

(1)

seq(f(k*N/4+1,(k+1)*N/4), k=0..3);

31375., 93875., 156375., 218875.

(2)

Threads:-Seq(f(k*N/4+1,(k+1)*N/4), k=0..3);

31218.+j, 93875., 156375., 218875.

(3)

Threads:-Seq(f(k*N/4+1,(k+1)*N/4), k=0..3);

31375., 93875., 156375., 218875.

(4)

Threads:-Seq(f(k*N/4+1,(k+1)*N/4), k=0..3);

31900., 94170., 156375., 218875.

(5)

 


Download threads!.mw

is possible to solve this pde via maple?

m1.mwm1.mw
 

restart

sys := [-(-r^2+1)*(diff(theta(r, z), z))+(diff(theta(r, z), r)+r*(diff(theta(r, z), r, r)))/r+diff(theta(r, z), z, z)+(diff(theta(r, z), r))*(diff(sigma(r, z), r))+(diff(sigma(r, z), z))*(diff(theta(r, z), z))+(diff(theta(r, z), r))^2+(diff(theta(r, z), z))^2 = 0, -(-r^2+1)*(diff(sigma(r, z), z))+(diff(sigma(r, z), r)+r*(diff(sigma(r, z), r, r)))/r+diff(sigma(r, z), z, z)+(diff(theta(r, z), r)+r*(diff(theta(r, z), r, r)))/r+diff(theta(r, z), z, z) = 0]; IBCs := {sigma(1, z) = 1, sigma(r, 0) = 1, theta(1, z) = 1, theta(r, 0) = 1, (D[1](sigma))(0, z) = 0, (D[1](theta))(0, z) = 0, (D[2](sigma))(r, 1) = 0, (D[2](theta))(r, 1) = 0}

[-(-r^2+1)*(diff(theta(r, z), z))+(diff(theta(r, z), r)+r*(diff(diff(theta(r, z), r), r)))/r+diff(diff(theta(r, z), z), z)+(diff(theta(r, z), r))*(diff(sigma(r, z), r))+(diff(sigma(r, z), z))*(diff(theta(r, z), z))+(diff(theta(r, z), r))^2+(diff(theta(r, z), z))^2 = 0, -(-r^2+1)*(diff(sigma(r, z), z))+(diff(sigma(r, z), r)+r*(diff(diff(sigma(r, z), r), r)))/r+diff(diff(sigma(r, z), z), z)+(diff(theta(r, z), r)+r*(diff(diff(theta(r, z), r), r)))/r+diff(diff(theta(r, z), z), z) = 0]

 

{sigma(1, z) = 1, sigma(r, 0) = 1, theta(1, z) = 1, theta(r, 0) = 1, (D[1](sigma))(0, z) = 0, (D[1](theta))(0, z) = 0, (D[2](sigma))(r, 1) = 0, (D[2](theta))(r, 1) = 0}

(1)

NULL


 

Download m1.mw

 

convert(...,Int) in Maple 2018.2 works for fourier, invfourier, laplace, but does not work for invlaplace.  

Why is that? Is there a workaround?

expr:=fourier(f(x), x, w):
convert(expr,Int);

expr:=invfourier(f(w), w, x):
convert(expr,Int);

expr:=laplace(f(s),s,t):
convert(expr,Int)

expr:=invlaplace(f(s),s,t):
convert(expr,Int)

Was expecting to see the Mellin's inverse formula.

Maple 2018.2 on windows 10

 

How can I calculate the Euler-Lagrange equation from the Lagrangian density from Gauged Baby Skyrme model in maple using the physics package? Here, the rules of the operation in the inner space are the same that of the vectors conventional: dot and cross products, etc...
Following below the Lagrangian density.

Errata:

Hello,

every time I input a formula I get:

Typesetting:-mparsed(x^2 +5 -2,x^2+3; "_noterminate")

I can't get rid of this error: this is very basic, what happened?

TIA, Roberto

 

i want to gain diff(p(t), t) and diff(q(t), t) and Jacobian matrix
 according to the attached pdf file.

please help me.

thanks

simplify.mw
 

k := diff(a(t), t) = -mu*a(t)-(1/4)*alpha6*a(t)*sin(gamma(t))

diff(a(t), t) = -mu*a(t)-(1/4)*alpha6*a(t)*sin(gamma(t))

(1)

j := a(t)*(diff(gamma(t), t)) = 2*a(t)*sigma-(6*(1/8))*(alpha1-alpha2+(1/3)*alpha3)*a(t)^3-(1/2)*alpha6*a(t)*cos(gamma(t))

a(t)*(diff(gamma(t), t)) = 2*a(t)*sigma-(3/4)*(alpha1-alpha2+(1/3)*alpha3)*a(t)^3-(1/2)*alpha6*a(t)*cos(gamma(t))

(2)

"p(t):=a(t)*cos(gamma(t))"

proc (t) options operator, arrow, function_assign; a(t)*cos(gamma(t)) end proc

(3)

"q(t):=a(t)*sin(gamma(t))"

proc (t) options operator, arrow, function_assign; a(t)*sin(gamma(t)) end proc

(4)

diff(p(t), t)

(diff(a(t), t))*cos(gamma(t))-a(t)*(diff(gamma(t), t))*sin(gamma(t))

(5)

(-mu*a(t)-(1/4)*alpha6*a(t)*sin(gamma(t)))*cos(gamma(t))-a(t)*(2*sigma-(6*(1/8))*(alpha1-alpha2+(1/3)*alpha3)*a(t)^2-(1/2)*alpha6*cos(gamma(t)))*sin(gamma(t))

(-mu*a(t)-(1/4)*alpha6*a(t)*sin(gamma(t)))*cos(gamma(t))-a(t)*(2*sigma-(3/4)*(alpha1-alpha2+(1/3)*alpha3)*a(t)^2-(1/2)*alpha6*cos(gamma(t)))*sin(gamma(t))

(6)

diff(p(t), t)

2*t

(7)

``


subs.pdf

Download simplify.mw

 

 

Hi, I'm using Maple 2018 and I tried to run coding from https://www.maplesoft.com/applications/view.aspx?sid=4194&view=html

however, it said : unable to parse. I figured out that the problem maybe is in the if loop. though it seems perfectly fine, but it has some goto commands that i cannot search on maple website. does this mean that the goto cannot be used here and should be replaced? if yes, then how? 

i am still learning on how to use maple. any help would be much appreciated. thank you!

this is the coding for if loop:

 

label_7;

rv:=vector([p1(x1pt,x2pt),p2(x1pt,x2pt)]):

numgeval:=numgeval+1;

printf("%5d (%8.4f,%8.4f)",numIter,rv[1],rv[2]);

max:=n;

mg:=convert(sqrt(dotprod(rv,rv)),float);

printf("%12.4f",mg);

if(mg<tol or numIter>=max) then

goto(label_6);

else

numIter:=numIter+1;

fi;

v1:=x1pt+t*rv[1];

v2:=x2pt+t*rv[2];

newt:=evalf(subs({x1=v1,x2=v2},f1));

numfeval:=numfeval+1;

lam:=fsolve(diff(newt,t)=0,t,maxsols=1);

nv1:=evalf(subs({t=lam},v1));

nv2:=evalf(subs({t=lam},v2));

printf(" (%8.4f,%8.4f)%13.4f\n",x1pt,x2pt,lam);

x1pt:=nv1;

x2pt:=nv2;

goto(label_7);

label_6;

printf("\n\n-----------------------------------------");

printf("---------------------------------------------");

printf("\n\n Approximate Solution: ");

printf(" (%8.4f,%8.4f)\n",x1pt,x2pt);

Fvalue:=evalf(subs(x1=x1pt,x2=x2pt,f));

printf(" Maximum Functional Value: ");

printf("%21.4f",Fvalue);

printf("\n Number gradient evaluations:");

printf("%22d",numgeval);

printf("\n Number function evaluations:");

printf("%22d",numfeval);

printf("\n\n-----------------------------------------");

printf("---------------------------------------------");

end:

hi.

According to the fhgure attaceh how i can gain the equation (2-27) . I write the equation (2-26) in maple but I couldnot to gain that result.

If possible to reach equation via maple?

Thanks

diff.mw
 

restart

FC := (1/2)*W_m^2*(c1*x^2+c2*y^2)+(E.(h^2))*W_m^2*(sum(An*((sinh(n*Pi/lambda)+n*Pi*cosh(n*Pi/lambda)/lambda)*cosh(2*n*Pi*y/a)-2*n*Pi*y*sinh(n*Pi/lambda)*sinh(2*n*Pi*y/a)/a)*cos(2*n*Pi*x/a)/(n^2*(sinh(n*Pi/lambda)*cosh(n*Pi/lambda)+n*Pi/lambda))+Bn*((sinh(n*Pi*lambda)+n*Pi*lambda*cosh(n*Pi*lambda))*cosh(2*n*Pi*x/b)-2*n*Pi*x*sinh(n*Pi*lambda)*sinh(2*n*Pi*x/b)/b)*cos(2*n*Pi*y/b)/(lambda^2*n^2*(sinh(n*Pi*lambda)*cosh(n*Pi*lambda)+n*Pi*lambda)), n = 1 .. n))

Warning,  computation interrupted

 

S := diff(FC, x); SS := diff(S, x)

g := subs(x = (1/2)*a, SS)

0

(1)

coeff(g, sinh(n*Pi/lambda))

0

(2)

``


 

Download diff.mw

why pdsolve does not work?

Q and alpha are constant. I want to find f(x,y).

Thanks
 

"restart: w(x,y) :=Q*sin^(2)(Pi*x)*sin^(2)(Pi*y)"

proc (x, y) options operator, arrow, function_assign; Q*sin(Pi*x)^2*sin(Pi*y)^2 end proc

(1)

PDE := diff(f(x, y), x, x, x, x)+2*(diff(f(x, y), x, x, y, y))/alpha^2+(diff(f(x, y), y, y, y, y))/alpha^4+((diff(w(x, y), y, y))*(diff(w(x, y), x, x))-(diff(w(x, y), x, y))^2)/alpha^2

diff(diff(diff(diff(f(x, y), x), x), x), x)+2*(diff(diff(diff(diff(f(x, y), x), x), y), y))/alpha^2+(diff(diff(diff(diff(f(x, y), y), y), y), y))/alpha^4+((2*Q*sin(Pi*x)^2*Pi^2*cos(Pi*y)^2-2*Q*sin(Pi*x)^2*sin(Pi*y)^2*Pi^2)*(2*Q*Pi^2*cos(Pi*x)^2*sin(Pi*y)^2-2*Q*sin(Pi*x)^2*sin(Pi*y)^2*Pi^2)-16*Q^2*sin(Pi*x)^2*sin(Pi*y)^2*Pi^4*cos(Pi*x)^2*cos(Pi*y)^2)/alpha^2

(2)

pdsolve(PDE)

``


 

Download PLATE.mw

Hi,

I submit you this strange result:
for somenumerical  values of a, b, c  (a, b, c real and b > a), Maple 2018 is not able to compute the mean of
c*U where U is a Uniform random variable with support [a, b].


 

restart:

with(Statistics):

interface(version);

`Standard Worksheet Interface, Maple 2018.0, Windows 7, March 10 2018 Build ID 1298750`

(1)

z := .4070716688*RandomVariable(Uniform(0.12-0.02*0.12, 0.12+0.02*0.12));
Mean(z);

.4070716688*_R

 

Error, (in Statistics:-Mean) the expression does not have a taylor expansion at t = 0

 

z := .4070716688*RandomVariable(Uniform(a, b));
Mean(z);
subs({a=0.12-0.02*0.12, b=0.12+0.02*0.12}, %);

.4070716688*_R0

 

.2035358344*a+.2035358344*b

 

0.4884860026e-1

(2)

 


 

Download Mean.mw


PLEASE: Maple still fails if I replace  a = 0.12 -0.02*0.12 by its value 0.1174
                                                                       and b = 0.12+0.02*0.12 by its value 0.1224
                   

This is incomprehensible and could hide a more profound problem.

What's going on here? Am I missing something, or is it a bug? If it's a bug, then it's by far the deepest and most profound bug that I've ever found or seen in Maple (and I've seen thousands over the decades). And since that surprises me, my guess is that I'm missing something obvious.

restart:
Op:= (R,F)-> F(['R()'$2]):
Op(rand(1..9), [f,f]);
                     [f([7, 6]), f([2, 4])]

The expected output is [f([7,6]), f([7,6])]. The same thing happens if I replace with seq, or if I replace -> with proc.

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