here i have four odes

diff(x(t),t)=f(x,y,z,w); diff(y(t),t)=g(x,y,z,w);diff(z(t),t)=h(x,y,z,w); diff(w(t),t)=k(x,y,z,w)

whrer f,g,h and k are known nonlinear functions? Then how can i get the graph of (x,y)near some point,eg (0,0), by the numeric method? Thank you very much!

Hi, one of our (potential) customers asked me if Maple is able to compute something...um... difficult. There is a thing called Primal Linear Program, which is given. The customer wants to compute the related dual program in a symbolic way. Is there a Package already implemented for such a thing ? I think it is related to business studies, anyhow. Thanks

hi all,

                            I  have a program written using Matlab, how can I change it into a program written using Maple.

the program:

% THE
% MATLAB

function [xmin, fxmin, iter] = PSO

%%%
success = 0;      

I use the MaxFlow command from the GraphTheory package, but I don't understand the results that I get.
The max flow value is okay, but the matrix in which the flows from node to node are given, is not what I expected.

Is this problem caused by the fact that the graph is not directed? I don't want to use a directed graph, because flows can choose only one of both directions.

H:=Graph(6,{{1,2},{1,3},{2,4},{4,6},{3,5},{5,6},{4,5}},weighted):
DrawGraph(H,style=spring);
MaxFlow(H,1,4);

As a solution I get:

Hej,
i'm quite new to maple and i want your advice /guidance(in fact i'm desperate)

in order to solve a system of 2 pdes coupled with 4 odes.
the pdes are :

diff((r1(t)*C1(t)+r2(t)*C2(t))*T(z,t),t)=diff(k(T(z,t))*diff(T(z,t),z),z)+Q*r1(t)

diff(e(t)*Y(z,t),t)=diff(D(Y(z,t))*diff(Y(z,t),z),z)-(B*exp(T(z,t))*r1(t)

odes:
diff(r1(t),t)=-(A*exp(T(z,t))+B*exp(T(z,t)))*r1(t)

diff(r2(t),t)=A*exp(T(z,t)*r1(t)

diff(r3(t),t)=B*exp(T(z,t)*r1(t)