function rr=hoffrun(shell,tt)

global po sigma1 Ro1 k amp mul f rhol Gs mus 

%generates R(t) curves for fitting data against
%parameter values

dRo1 = 1.50e-6;      %bubble initial radius(m)

dGs=shell(1)*12*1e6*1e-9*dRo1^2; %composite quantity including ds=1nm
dmus=shell(2)*12*1e-9*dRo1^2; %composite quantity including ds=1nm


dpo = 1.0e5;        %ambient pressure (Pa)
dsigma1 = 0.07;     %equlibrium gas/shell surface tension (N/m)
dmul = 1.0e-3;      %surrounding fluid viscosity (Pa.s)
drhol = 1000.0-5;     %surrounding fluid density (kg/m^3)
k = 1.4;              %ratio of gas specific heats
df = 2.0e6;         %insonation frequency (Hz)
damp = 5.0e4;     %insonation pressure amplitude (Pa) 


%non-dimensionalise
rhol=drhol*(dRo1*2*pi*df)^2/dpo;
mul=dmul*df*2*pi/dpo;   
Ro1=dRo1/dRo1;
sigma1=dsigma1/(dpo*dRo1);      
po=dpo/dpo;
f=df/(2*pi*df); 
amp=damp/dpo;
Gs=dGs/dpo/dRo1^3;
mus=dmus*2*pi*df/dpo/dRo1^3;
f=df/(2*pi*df); 


%call function%
%options=odeset('MaxStep',1/f/100);
[t,r] = ode45('lrp',tt,[Ro1; 0]); 
%[t,r] = ode45('lrp',[0 tmax],[Ro1; 0]);

rr=r(:,1);

%plot radius/time curve
%figure
%plot(t,r(:,1),'-.k','linewidth',2)
% %axis([0,15,.999*min(r(:,1)),1.002*max(r(:,1))])
% %axis([0,10,min(r(:,1))*.95,1.1*max(r(:,1))])
% xlabel('Time (us)','fontsize',20)
% ylabel('Radial amplitude (R/Ro)','fontsize',20)

end