change imaginary check from abstol to reltol

dmd.m

@@ -72,7 +72,9 @@ classdef dmd < handle
             end
             
             X2hatComplex = obj.Phi*obj.Lambda*(obj.Phi\obj.X);
-            assert(norm(imag(X2hatComplex)) <= 1e-6);
+			if (norm(imag(X2hatComplex))/norm(X2hatComplex) >= 1e-6)
+				warning('rel norm of imaginary component of X2hat nontrivial: %e. Proceeding anyway.',norm(imag(X2hatComplex))/norm(X2hatComplex))
+			end
             X2hat = real(X2hatComplex);
             
         end
@@ -97,6 +99,11 @@ classdef dmd < handle
             end
             
             assert(norm(imag(xhat)) <= 1e-6);
+%             assert(norm(imag(xhat)) <= 1e-6);
+			if (norm(imag(xhat))/norm(xhat) >= 1e-6) % rel norm of imag components 
+				warning('rel norm of imaginary component of X2hat nontrivial: %e. Proceeding anyway.',norm(imag(xhat))/norm(xhat))
+			end
+			
             xhat = real(xhat);
             predictTime = toc;
             if(obj.verbose)