% sys3plot.m 
% Generates three plots on page pertaining to solutions of a linear ODE 
% system. Plots include numerically generated solution(s) as functions 
% of t (ODE45), phase plane, and user-derived solution(s) or eigenvalues. 
% There is a choice of user-derived or eigenvalue plots. Necessary data, 
% information, and choices are entered via INITSYS.M  

figans=input('Do you already have a separate figure window for sys3plot? (y/n) ','s'); 
if figans=='n'; 
 numfig=figure; 
end 
figure(numfig) 
clf 
set(numfig,'DefaultAxesFontSize',8) 

subplot(2,2,2) 
plot(s,y(:,1),'b-',s,y(:,2),'r--') 
title('Solution plot, ODE45') 
xlabel('x1 = solid,  x2 = dashed') 
grid on 

subplot(2,2,4) 
grid off 
pplane2f(eqn_name,N,'x2 (vertical) vs x1 (horizontal)','') 
plot(y(:,1),y(:,2)) 
title('Phase Plane, ODE45') 
hold off 

if sum(abs(symbolicplot))~=0 
 if sum(abs(symbolicplot))==sum(abs('solutions'))  
  subplot(2,2,3) 
  if min(x0vec)<max(x0vec) 
  	  ax=[t0,tf,min(x0vec),max(x0vec)]; 
  else  
	  ax=[t0,tf,min(x0vec),max(x0vec)+1]; 
  end 
  x0=x0vec(1); 
  [tplot,x1slnplot]=plotslnf(x1symb,ax,tf,x0); 
  x0=x0vec(2); 
  [tplot,x2slnplot]=plotslnf(x2symb,ax,tf,x0); 
  plot(tplot,x1slnplot,'b-',tplot,x2slnplot,'r--') 
  title('Solution plot, Symbolic') 
  xlabel('x1 = solid,  x2 = dashed') 
  grid on 
  hold off 
 end 

 if sum(abs(symbolicplot))==sum(abs('phase'))  
  subplot(2,2,3) 
  grid off 
  pplane2f(eqn_name,N,'','') 
  plottitle='Phase Plane, Symbolic'; 
  plotxytf(x1symb,x2symb,t0,tf,'r-',plottitle)
 hold off 
 end 

 if sum(abs(symbolicplot))==sum(abs('eigenvals')) 
  subplot(2,2,3) 
  plot(real(eigvals),imag(eigvals),'o') 
  hold on 
  ax=axis; 
  dxorigin=(ax(2)-ax(1))/10; 
  dyorigin=(ax(4)-ax(3))/10; 
  plot([ax(1)-dxorigin,ax(2)+dxorigin],[0,0],[0,0],...
   [ax(3)-dyorigin,ax(4)+dyorigin]) 
  axis([ax(1)-dxorigin,ax(2)+dxorigin,ax(3)-dyorigin,ax(4)+dyorigin]) 
  xlabel('Eigenvalues') 
  hold off 
 end 
end