Problems with eigendecomposition of a big stochastic matrix

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I face the following problem. I generate a big $1202 \times 1202$ stochastic matrix $Q$ whose columns adds to $1$ (up to numeric precision). The elements of $Q$ are in $[0,1]$. I use the eigendecomposition

[ R, D ] = eig( Q )

and I compute

L = inv( R )

I have NO warning that R is close to singular and the elements of R may have big imaginary parts. (I tried to use [ R, D, L ] = eig( Q )but R*L dose not provide an identity matrix).

I get a result where:

Q ~= real( R*D*L )

At the end I have better results in matlab just by using

Q^200000 than R*D^200000*L.

Is there any explanation for this behavior?