1 files changed, 28 insertions, 0 deletions
diff --git a/60/DEPENDENCIES/modifiedEuler.sce b/60/DEPENDENCIES/modifiedEuler.sce
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+++ b/60/DEPENDENCIES/modifiedEuler.sce
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+function [u,t] = modifiedeuler(u0,t0,tn,h,f)
+
+//modifiedeuler 1st order method solving ODE
+//  du/dt = f(u,t), with initial 
+//conditions u=u0 at t=t0.  The 
+//solution is obtained for t = [t0:h:tn]
+//and returned in u
+
+umaxAllowed = 1e+100;
+
+t = [t0:h:tn]; u = zeros(t); n = length(u); u(1) = u0;
+
+for j = 1:n-1
+    k1=h*f(t(j),u(j));
+    k2=h*f(t(j)+h/2,u(j)+k1/2);
+    u(j+1) = u(j) + k2;
+   if u(j+1) > umaxAllowed then
+           disp('Euler 1 - WARNING: underflow or overflow');
+           disp('Solution sought in the following range:');
+           disp([t0 h tn]);
+          disp('Solution evaluated in the following range:');
+          disp([t0 h t(j)]);
+           n = j; t = t(1,1:n); u = u(1,1:n);
+    break;
+    end;
+end;
+
+endfunction
+\ No newline at end of file