Hello, everybody!

If it is convenient for you, I wish you can help me review the following program. Thank you very much in advance. I want to obtain the coefficient values of c0, n, s0, ks, h1, h2, kp, A, B for the ODE system.

restart;
cdm_ode := diff(y1(t), t) = c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(1-y2(t)), diff(y2(t), t) = ks*y2(t)^(1/3)*(1-y2(t)), diff(y3(t), t) = h1*(1-y3(t)/h2)*c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(sigma*(1-y2(t))), diff(y4(t), t) = (1/3)*kp*(1-y4(t))^4, diff(y5(t), t) = A*B*y1(t)^(B-1)*c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(1-y2(t)), diff(y6(t), t) = y6(t)*c0*(y6(t)*(1-y3(t))/(s0*(1-y4(t)*(1-y5(t)))))^n/(1-y2(t));

tol_t := 3600;


sol := dsolve([cdm_ode, y1(0) = 0, y2(0) = 0, y3(0) = 0, y4(0) = 0, y5(0) = 0, y6(0) = 175], numeric, range = 0 .. tol_t, output = listprocedure, parameters = [c0, n, sigma, s0, ks, h1, h2, kp, A, B]);

err := proc (c0, n, s0, ks, h1, h2, kp, A, B) local st1, st2, sv1, sv2, sv; sol(parameters = [c0, n, 175, s0, ks, h1, h2, kp, A, B]); st1 := subs(sol, y1(t)); sv1 := [st1(1), st1(100), st1(210), st1(2500), st1(2800), st1(3000)]; sol(parameters = [5.7/10^6, 10.186, 175, 200, 1/20000000, 10000, .269, 1.5/10^7, 1.5, 2]); st2 := subs(sol, y1(t)); sv2 := [st2(1), st2(100), st2(210), st2(2500), st2(2800), st2(3000)]; sv := add((sv1[i]-sv2[i])^2, i = 1 .. 6); sv end proc;

with(GlobalOptimization);
GlobalSolve(err, c0 = 0 .. 1, n = 1 .. 20, s0 = 150 .. 250, ks = 0 .. 1, h1 = 100 .. 15000, h2 = 0 .. .5, kp = 0 .. 1, A = .5 .. 2, B = 1 .. 5);

Error, (in GlobalOptimization:-GlobalSolve) `InertForms` does not evaluate to a module

Hello
Is there a Maple-function that returns a number of transpositions needed to transform a list into a list with some particular order? Actually, I need just a parity of a number of transpositions. All elements of a list are different.

For example, one needs 4 (even) transpositions to transform a list [w,x,y,z] into a list [y,x,z,w]:
[w,x,y,z]->[w,y,x,z]->[y,w,x,z]->[y,x,w,z]->[y,x,z,w]

Thank you

Please I need someone to help out with how to solve the below ODE numerically using finite difference method with the necessary maple code:

█( S〗_h〗^' (t)=Λ_h-αβ_m I_v S_h-μ_h S_h+πI_m,  

〖I_m〗^' (t)=αβ_m I_v S_h-(σ_m+π+μ_h ) I_m

〖 S〗_v〗^' (t)=Λ_v-αβ_v I_m S_v-μ_v S_v

〖I_v〗^' (t)=αβ_v I_m S_v-μ_v I_v )

The initial conditions can be assumed. Suppose i want to include controls, how do I solve the problem and equally plot the graph.

Thank you.

ADENIYI MICHAEL

http://i.imgur.com/JGObjn5.png

I tried with and without evalf. Do I need to import something? or something like with Linear Algebra? 

i am solving 3 ODE question with boundary condition. when i running the programm i got this error.. any one could help me please.. :)

Download tyera(a).mw

I'm using maple to write text to an external text file. My code is

f := x-> arcsin(x);

file := "C:\\example.txt":

fopen(file,WRITE,TEXT):

fprintf(file,"%a",f(1)):

fclose(file):

The problem is that the output in my file example.txt reads "1/2*Pi" and I'd like it to be "1/2*pi". In other words, is it possible to have maple scan my file and replace the occurances of "Pi" with "pi"?

Is there a way to do the following on Maple:

I want Maple to use Jacobi's method to give an approximation of the solution to the following linear system, with a tolerance of 10^(-2) and with a maximum iteration count of 300.

The linear system is

x_1-2x_3=0.2

-0.5x_1+x_2-0.25x_3=-1.425

x_1-0.5x_2+x_3=2

Thanks.

Hello,

I'd like to clean up my project a bit. In a chapter of a project I made lots of calculations and declared a many (30) variabeles (Table, Numeric, Formula, ..)

Is there a way to remove all variable's except specified one's? (If it is possible I don't want to use an external file to write it to and read it back after a restart)

Is there a way to do a "restart" and preserve only the one's (2) that I need for my next chapter?
Or if not, without a "restart" and remove all variables except specified one's?

Thanks for your help, 

What’s the simplest way to solve an algebraic equation in the complex domain?

For example,

I*(a+3*b)+2*b+5*a = 3+2*I

where a and b are real numbers.

One of my post graduate students chose the theme "Discrete Wavelet analysis of medical signals with Maple" for her thesis. I test, is it possible to support such reearch be Maplesoft &  what may be the form of such support, if it is possible?

• here is an exercise I got from a text book                                                                                                              calculate the first 10 terms of the following sequence :                                                                                              

                                                                                                                                                             u[n+1]=1/2(u[n]+2/u[n]) n>=0                                                                                                                          

• estimate the differences u[3]-sqrt(2) , u[4]-sqrt(2), u[5]-sqrt(2), and u[6]-sqrt(2) with a precision of 50 numbers                                    
• what can we conjecture about the sequence ?
• how to prove that conjecture with MAPLE ?

This is pretty similar to my last question. but I found this maple code on a website that is suppose to find a vertex coloring of a graph G. The output is is supposed to be a list for example like [3, table([y = 1, k = 2, c = 2, m = 3, h = 1, x = 1] where the first part (in this case 3) is the number of colors and 1,2,3 in the second part are the colors to which each vertex is assigned.  However, no matter what graph I run this on I get everything equal to 1. such as [1, table([y = 1, k = 1, c = 1, m = 1, h = 1, x = 1])]. Why is this happening?  

color:=proc(G)
  local i, j, C, U, V, total_used;
  V:=Vertices(G); total_used:=1;
  C[V[1]]:=1;

  for i from 2 to nops(V) do
    C[V[i]]:=0;
  end do;

  for i from 2 to nops(V) do
    U:={};
      for j from 1 to nops(neighbors(V[i], G)) do
      U:=U union C[neighbors(V[i], G)[j]];
       end do;
    j:=1;
    while member(j, U) do
      j:=j+1;
     end do;

    C[V[i]]:=j;
    if j>total_used then
      total_used:=j;
    end if;
   end do;
  [total_used, eval(C)];
end:

So the pseudocode I'm trying to translate into maple is for the greedy vertex coloring algorithm.

The pseudo code is:

Initialize:
1. for i = 1 to n do
2. f[i] := 0 (: no color assigned yet to vertex i :)
3. end(for)
Main loop:
4. for i = 1 to n do
5. let f[i] be the smallest positive integer
which is not in the set {f(j) : j ∈ adj[i]}
6. end(for)
7 return f

The closest I've gotten though is:

greedy := proc (G)

local i, j, n, k, L::list;

description "Take simple graph G and return a coloring of the vertices with at most Delta(G)+1 colors";

n := nops(Vertices(G));
L := [seq(x, i = 1 .. n)];
L := subsop(1 = c(1), L);
j := 1;
for i from 2 to n do
L[Vertices(G)[i]] := c(0)
end do;

for i from 2 to n do
   for k to i do
        if member(Vertices(G)[i], Neighbors(G, Vertices(G)[k])) then j := j+1
       end if; 
   end do;
L[Vertices(G)[i]] := c(j)
end do;
return L;
end proc;

Basically my procedure is returning more than delta+1 colors for most graphs, how can I edit it to fix this? I'm guessing the problem is somewhere in my nested loops. Also, I cannot use commands like greedycolor or isvertexcolorable. Thanks.

Hi,

Thank you very much for your idea in previous discussion: this is the link.

http://www.mapleprimes.com/questions/202744-Calculs-Using-Maple

I asked how can I plot the phase portrait of this system

Sys1 := {diff(r(t),t) = r(t)^2*sin(theta(t)), diff(theta(t),t) = -r(t)^2*(-2*cos(theta(t))^2+1)};

I get this answer:

1) For me it's not necessary to give an initial condition to plot the pharse portrait.

2) What is the line in this phase portrait.

3) Here, I try a second method using Matlab code, I get:

and this is the code:

[r, theta] = meshgrid(0:pi/4:2*pi, 0:pi/4:2*pi);
rdot =r.^2.*sin(theta) ;
thetadot = r.^2.*(1-2*sin(theta).^2);
quiver(r,theta,rdot,thetadot)
xlabel('r')
ylabel('theta')

the arrow in the phase portrait are not the same.

Can someone give me more clear information about this problem.

Many thinks.

Hi, I'm trying to write a maple procedure to differentiate a function from first principles and so far I have

First_Principle := proc (f); for f do A := simplify((f(x+h)-f(x))/h); Limit(A, h = 0) = limit(A, h = 0) end do end proc

and from there I have no idea where to go. Does anybody have any ideas? Thanks!