Phase Portrait of ODE system

I need to generat the phase portrait of the ode system given, where r,p,c and b are given constants

dv/dt=rv-pvx

dx/dt=cv-bx

Below matlab code is what I have gotten so far

However, how do I implement ode45 functione here?

I would like to use ode45 function, but was not sure how to do so.

If some one could guide me through how to use ode45 function to generate the phase portrait, it will be much appreciated.

% Part IIa. Base Case
% Phase Portrait
clc
clear
close all
%
%
r=2.5;
p=2;
c=0.1;
b=0.1;
%
[x,v]=meshgrid(0:1:5, 0:1:5);
dx=r.*v-p.*v.*x;
dv=c.*v-b.*x;
streamslice(x,v,dx,dv,'filled');
quiver(x,v,dx,dv);

Answer 1

[Alan Stevens]

Do you mean something like this:

% Part IIa. Base Case
% Phase Portrait
%
%
r=2.5;
p=2;
c=0.1;
b=0.1;
%
% [x,v]=meshgrid(0:1:5, 0:1:5);
% dx=r.*v-p.*v.*x;
% dv=c.*v-b.*x;
% streamslice(x,v,dx,dv,'filled');
% quiver(x,v,dx,dv);

% Set time interval as you desire (arbitrary values used here)
tspan = [0 50];
% Set initial conditions as you desire (arbitrary values used here)
X0 = [0.2 0];  % [x0 v0]

[t, X] = ode45(@(t,X) rate(t,X,r,p,c,b),tspan,X0);
x = X(:,1); v = X(:,2);

plot(x,v),grid
xlabel('x'),ylabel('y')

function dXdt = rate(~,X,r,p,c,b)

         x = X(1); v = X(2);
         dXdt = [r*v-p*v*x;
                 c*v-b*x];
end

Answer 2

[Steven Lord]

You could use ode45 with the 'OutputFcn' option set to @odephas2 using odeset, as shown in this Answers post.