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Hi all,

Anyone knows how to see a manual for DirectSearch:-GlobalSearch that explains what is done inside the function?

I tried to write "help(DirectSearch:-GlobalSearch)" and nothing. It opened an empty page written (no matches found). Is there any help for this function so I can know what's going on there?

More specifically, I'm trying solve the optimization probelm min(||Ax-b||_p) s.t. ||x||=1.

where A is a given matrix of size (n \times d)

b is a given vector of size (n \times 1)

p>0 is a scalar

and x is an unkown vector of size (d \times 1) that should be a unit vector.

I used DirectSearch:-GlobalSearch to solve this optimization problem. But since it's a non-convex optimization probelm, the function doesn't always return the optimal value. I want to read the manual of the function to understand what is done there and for which cases there are most chances that the function will not return the optimal value.

Thanks

Given any threshold value, I am interested in obtaining a quantity of interest using the inverse negative binomial distribution. This requires extracting the value from the discrete CDF and I am using the Quantile(X, threshold value) function.

The parameters of the NBD are given as r and p and the routine I have written (attached) works in some cases, but I have noticed that, for small values of p, the Maple program runs for excessive times to attempt to output the Quantile solution. For instance, if p = 0.3, the solution is fast but when p = 0.003, Maple continues to evaluate the solution with no result (I have interrupted computations after 2 hours).

In the attached example, p is set to 1.965 and r is 0.5. The threshold value is 0.98 and the associated solution, Q, for this value is determined to be Q=7.

Does anybody know how to help with this? I would be grateful for any help along the way. 

Is it possible to output to the console without a new line being added. The code:

prints each number on a separate line. I want to print them all on the same line.

Hi

I want to write a code to show that

Please check the following code:

restart;
with(VectorCalculus):
SetCoordinates(cartesian[x, y, z]): 
g1 := proc (u1, u2, u3, s)
local N, u, n, intr1, intr2, intr3, R1, R2:
u := VectorField([u1, u2, u3]): 
N := Gradient(s): 
n := N/sqrt(add(N[k]^2, k = 1 .. 3)): 
intr1 := solve(subs(z = 0, s), y): 
intr2 := solve(subs(z = 0, y = 0, s)): 
R1 := int(int(subs(z = solve(s, z)[1], u . n), y = intr1[1] .. intr1[2]), x = intr2[1] .. intr2[2], numeric):
intr1 := solve(s, z): 
intr2 := solve(subs(z = 0, s), y):
intr3 := solve(subs(z = 0, y = 0, s)): 
R2 := evalf(int(int(int(Del . u, z = intr1[1] .. intr1[2]), y = intr2[1] .. intr2[2]), x = intr3[1] .. intr3[2])):
print(R1, R2) 
end proc

It seems that different answers are obtained.

g1(x, 1, z, x^2+y^2+z^2-2);
                   6.664324407, -23.69537567
 

Hello!

I am trying to determine the type of Lie algebra originating from Killing vectors. However, Maple says that some variable x is protected (though, I guess, it shouldn't even be in the L). Is there any way to solve this issue?

Best regards, 
Nick

error.mw

Download error.mw

Hi,

I have this fonction  solve({f(x,y)});  giving this  for example { x = 13, y =259 }

how can reuse the result for a an other fonction.

Thanks

Hi, 

I would like to have some references about the function PolyhedralSets:-PolyhedralSet.
I used it very recently before constructing the convex hull  (PolyhedralSets:-ConvexHull) of a set of 50 points.
After some minutes spent to wait for a solution, I was forced to stop the computation.
I randomly sampled 10 points, next 20, 30, ... from the original set of points and observed that the computational time was growing very fast with the number of points.

Could you please inform me about the algorithm Maple uses and about its complexity?

Last point: the original points are floating numbers and I used the transformation  T: x -->  rounf(10^k*x) / 10^k (PolyhedralSets:-PolyhedralSet operates only on rationals).
It seems that the computational time increases strongly as k increases too.

What are the limitations and best practices to use PolyhedralSets:-PolyhedralSet?

TI1

Hello, 

I am fairly new to using the Maple software, so I apologize if my question is completely idiotic. Apologies, also, because I could not manage to enter my code as code. When I pressed the button it made the whole text as a code. 

I run the following code to seek -if there are any- analytic solutions for the following differential equation.

odeplus := (r^2+L^2)^(5/2)*(diff(f(r), `$`(r, 2)))+((15/4)*r*(r^2+L^2)^(1/2)+3*(r^2+L^2)^(5/2)/r)*(diff(f(r), r))+M^2*f(r)/(r^2+L^2)^(5/2)-((5/2)*((r^2+L^2)^(1/2))(l-1)+(55/64)*r^2/(r^2+L^2)^(3/2)+(r^2+L^2)^(5/2)*(l^2+3*l+3/2)/r^2)*f(r)+(((r^2+L^2)^(1/2))(5+(5/2)*l)+(5/8)*r^2/(r^2+L^2)^(3/2)-(r^2+L^2)^(5/2)*(3/2+l)/r^2)*f(r) = 0

and then I do 

dsolve(odeplus, f(r))

The solutions that Maple returns is given in terms of DESol. Could anyone try and break it down for me? What is this telling me and if I can indeed from the output obtain analytic solutions? Is this some sort of operator acting on something? 

Thank you in advance. 

hi.

I can not gain answer for integral.

Best

int.mw
 

Download int.mw

I've been googling for a while for a built-in function that computes {binomial(n,k) mod p} in Maple. The closest I've come to finding an answer is here: https://www.mapleprimes.com/questions/200986-Binomial-Coefficients , where the answer is given for p=2 and the method uses Lucas' theorem and relies completely in the binary nature of the problem. Is there any such function? If not, what would the most efficient way to handle this numbers be? Thanks for the help!

This is probably a silly question, but...

given 

GST := AE+AI-ANB-AR-CP

how do i append [i] to each element of the list so I get

AE[i]+AI[i]-ANB[i]-AR[i]-CP[i]

this nearly gets it

(GST@`[]`)~(i);
 

I an unable to get a numerical result out of this triple integral.  Maple runs forever.  I stopped it after about half an hour:

Int(exp(-a^2-b^2-c^2),
    a=b^2/(4*c)..infinity, b=-infinity..infinity, c=0..infinity);
value(%);
evalf(%);

Is there a trick to make it work?

 How to display the result in the desired form in partial differential equation and also collect the same terms

i am attaching sample codes

restart:
with(DETools):
P[o](z):=C[o]*exp(lambda*z)+D[o]*exp(-lambda*z):
u[o](r,z):=(1-r^2)*diff(P[o](z),z):
v[o](r,z):=(2*r-r^3)*diff(P[o](z),z,z):
A1:=P[o](z)*u[o](r,z):
# we want the result out put  like this
A1 := lambda*(C[o]^2*exp(2*lambda*z)-D[o]^2*exp(-2*lambda*z))*(1-r^2):
A2:=P[o](z)*(1+r^2)+v[o](r,z)+A1:
#we want the  resultant output like this
A2:=lambda^2*(C[o]*exp(lambda*z)+D[o]*exp(-lambda*z))*(1+r^2+2*r-r^3)+A1:
 

hi , i have problem solving numerically, what should i do?
 

Download dsolve.mw