Runge Kutta (Matlab)
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Revision as of 05:00, 19 September 2005 by Harish gopalan (Talk | contribs)
% script file for initial value problems % uses Matlab ODE45 - Runge-Kutta method clear all; close all; % specification of Eta eta_low=0.0; eta_high=10.0; eta_cal = [eta_low eta_high]; % array of start and finish points finit = [0.0 0.0 0.3320]; % initial values for f fp fpp [eta f ] = ode45('state',eta_cal,finit); [eta f] figure; plot(eta,f); figure; plot(eta,f(:,2),'r') % only interested in velocity profile l=true; a_l=0; a_u=2; while (l) a=(a_l+a_u)/2; finit = [0.0 0.0 a]; % initial values for f fp fpp [eta f ] = ode45('filename',eta_cal,finit); % [eta f] ; if(abs(1-f(length(f),2))>0.1) if(f(length(f),2)>1) a_u=(a_l+a_u)/2; else a_l=(a_l+a_u)/2; end else l=false; end hold on; plot(eta,f(:,2)) % only interested in velocity profile end % Contents of filename %function initial = filename(t,f) %initial = [ f(2) , f(3) , -0.5*f(1)*f(3)]';