Hello,

I have a little question which is in the title.

It seems to me at the view of this example :

[x[i], y[i]] $ i=1..4;

seq([x[i], y[i]],i=1..4);

May you give me your feedback to be sure ?

Thank you 

Hi everyone...!

Can somebody tell me how to express this equation in Maple? 

x_ij <= z_kl ; ∀ i ∈ I: S(i)=k, ∀ j ∈ B: R(j)=l; 

Currently I'm dealing with containerization problem and have 4 indexes in the constraints (namely: i for item, j for container, k for shipment, l for route, S for Set of Shipment, and R for Set of Route) while x and z are binary variables. What I want to express is: (for example), item 1,2,3 are in shipment 1, item 4,5 are in shipment 2, etc etc. SO, if i = 1,2,3 then the value of k will be 1. If i = 4,5 then the value of k will be 2, etc. Same thing goes to j and l, (for example) if j = 1,2 then the value of l will be 1, etc etc. Further depcition is more or less like this:

S(i) = k

S(1) = 1

S(2) = 1

S(3) = 1

S(4) = 2

S(5) = 2

Thank you very much for the help.

I faced a very large eigenproblem during my research. The square matrix under consideration is of size more than 2^30 times 2^30. I have tried to deal with this problem by the QR algorithm with double implicit shift (more precisely, the Francis double step QR algorithm). I'm a very beginner of programming, but I tried as follows:

--------------------------------------------------------------------------------------------------

A := Matrix([[7, 3, 4, -11, -9, -2], [-6, 4, -5, 7, 1, 12], [-1, -9, 2, 2, 9, 1], [-8, 0, -1, 5, 0, 8], [-4, 3, -5, 7, 2, 10], [6, 1, 4, -11, -7, -1]]):
H := HessenbergForm(A):
p:=6:  
for p while p>2 do: 
q:=p-1: 
s:=H(q,q)+H(p,p):  
t:=H(q,q)*H(p,p)-H(q,p)*H(p,q): 
x:=(H(1,1))^(2)+H(1,2)*H(2,1)-s*H(1,1)+t: 
y:=H(2,1)*(H(1,1)+H(2,2)-s): 
z:=H(2,1)*H(3,2): 
for k from 0 to p-3 do:  
V:=Vector([x,y,z]):   
P:=Transpose(HouseholderMatrix(1/(Norm(V+exp(argument(V(1))*I)*Norm(V,2)*Vector(3,shape=unit[1]),2))*(V+exp(argument(V(1))*I)*Norm(V,2)*Vector(3,shape=unit[1])))):   
r:=max(1,k):
H[k+1..k+3,r..6]:=MatrixMatrixMultiply(Transpose(P),SubMatrix(H,[k+1..k+3],[r..6])):  
r:=min(k+4,6):
H[1..r,k+1..k+3]:=MatrixMatrixMultiply(SubMatrix(H,[1..r],[k+1..k+3]),P):   
x:=H(k+2,k+1):
y:=H(k+3,k+1):   
if k<3 then z:=H(k+4,k+1):   
end if: 
od: 
P:=GivensRotationMatrix(Vector([x,y]),1,2): 
H[q..p,p-2..6]:=MatrixMatrixMultiply(Transpose(P),SubMatrix(H,[q..p],[p-2..6])): 
H[1..p,p-1,p]:=MatrixMatrixMultiply(SubMatrix(H,[1..p],[p-1,p]),P): 
if abs(H(p,q))<10^(-20)*(abs(H(q,q))+abs(H(p,p))) then    H(p,q):=0: p:=p-1:q=p-1:  
elif abs(H(p-1,q-1))<10^(-20)*(abs(H(q-1,q-1))+abs(H(q,q))) then    H(p-1,q-1):=0: p:=p-2:q:=p-1:  
end if:  od:
--------------------------------------------------------------------------------------------------

It seemed that replacing 0 in a Hessenberg matrix by a non-zero element is not allowed. How can I remedy this?

Plus, can anyone tell me the problem of the above thing(it's not really a programming...;( ), please?

I would also appreciate it if someone let me know a better idea for a huge eigenproblem.

Thanks in advance.

What does one use to duplicate a procedure along with its remember table, so that they are distinct instances of said?

in LinearAlgebra Eigenvectors calculation.

So the above output startled me.  I have used the Maple Linear Algebra Eigenvalues, Eigenvectors commands many times with no problem.  Can any one explain to me what is going on.  The program correctly calculates the eigenvalues for the matrix which are all distinct for a real symmetric matrix, and thus should have three distinct non-zero eigenvectors, yet the eigenvectore command returns only zeros for the eigenvectors.  I calculated an eigenvector by hand corresponding to the eigenvalue of 1 and obtained (1, -sqrt(2)/sqrt(3), -1/sqrt(3).

So this is either a serious bug or I am going completely insane. 

es posible obtener la función del contorno de un dominio convexhull ?

 of equations from a set of solution after solve ?

what are these ways?

[a = s/RootOf(_Z^2-s^2+s), b = -RootOf(_Z^2-s^2+s)/s, c = RootOf(_Z^2-s^2+s)]

diff(F(x,F(x)), x);

how to differentiate this?

(D[1](F))(x, F(x))+(D[2](F))(x, F(x))*(diff(F(x), x))

how to find (D[1](F))(x, F(x)) and (D[2](F))(x, F(x)) ?

i guess need define new calculus for two variables

Limit((F(x+h,F(x+h)) - F(x,F(x)))/h, h = 0);

Limit((F(x+h,F(x)) - F(x,F(x)))/h, h = 0);
Limit((F(x,F(x+h)) - F(x,F(x)))/h, h = 0);

Limit((F(x+h,F(x,y)) - F(x,F(x,y)))/h, h = 0);
Limit((F(x,F(x+h,y)) - F(x,F(x,y)))/h, h = 0);

if inside F(x) is F(x,y)

it seems need to find the basic definition of F(x,y) first

if i define F(x,y) as

F := (x,y) -> min(x,y)/max(x,y);

i may be wrong, how to differentiate correctly?

Hi, friends!

I'm not a math =) but it is interesting

How can i solve this equation like the gambler's ruin with Maple's function rsolve

f(n)=0.5*f(n-1)+0.5*f(n+1), f(0)=1, f(6)=0

rsolve({f(n)=0.5*f(n-1)+0.5*f(n+1), f(0)=1, f(6)=0}, {f});

it returns this 

{f(n) = 7 f(5) - f(5) (n + 1)}

I don't understand :( 

for example Wolfram Alpha return the true result

Sorry for the uninformative title. I've never used Maple, but I'm willing to buy a student license and learn it. But before spending too much effort and money I need to know if it suits my needs.

Basically what I need to do is:

1) I have a positive definite symmetric matrix of size nxn, where n can range from 2 to inf. I don't know the elements, except the fact that the diagonal has ones everywhere. All I know is that the elements out of the diagonal are in the range [0,1)

2) I have to compute the lower triangular cholesky decomposition of this matrix, lets call it L.

3) I need to subtract from each element of L the mean of the elements in the respective column. Lets call this matrix L*

4) Then I need to evaluate another nxn matrix computed from the elements of L* following a simple pattern.

5) Finally I need to find the eigenvalues of this last matrix.

What I would ideally want is to get a symbolic representation of the n eigenvalues as symbolic functions of the (unknown) elements of the matrix at point 1.

I can drop the assumption of n being unknown, i.e. fix n=3 and get the 3 functions that, after replacing the right values, give me the eigenvalues, then fix n=4 and get 4 functions, etc.

Is this possible to do in maple?

Thank you

Hello,

I try to use a Catmull-Rom spline which has to match on several points.

I use a code extracted from the book "Geometry and curves with maple".

Here you can find an extract which is visible from google book :

I have slightly modified the initial procedure crom_2d. I didn't find the error in my procedure. May you help me to find the blocking point of my procedure ?

Here I attached my code:

CalculSplineMatmull-Rom.mw

Thank you for your help.

Compute the following multiple integral exactly and/or with 10 correct significant digits

Int(  exp( - add(x[i],i=1..10)^3),  seq(x[i]=0..1, i=1..10) );

  The problem is suggested by a previous post.

Hello everyone !

I have a problem when I want to calculate the following multiple integration numerically:

>evalf(Int(exp(sum(x[i],i=1..6)^2),[seq(x[i]=-1..1,i=1..6)]));
  value(%);

It doesn't work. But when I replace sum(x[i],i=1..6)^2 with sum(x[i],i=1..6), it works. Is there any feasible solution to my problem ?

Thank you for reading !

Dear Friends

In differential expressions(See Maple file) how to find coefficiets of dependent variable "u(x,t)" and "v(x,t)" and of their differentials ? There is command "dcoeffs(function)", but that work for single dependent variable only but in our case there are two dependent variables in consideration. There are other options like "indets", "specindex" but those do not work.

Download Coefficients_in_differential_expression.mw

Hello

I have an SEIR model.

Equation 5 is for disease death but I would like to plot the cumulative numbers of disease death which will be the integral of Equation 5. I added the integral inside odeplot but it is not working. Any idea  about  how to compute the integral ?

Maple code is attached

Thank you

code.mw