Question: Eigenvalue Ordering Problem

Hi,

     I have a a matrix with one symbol and all others are numbers. I got this from doing 

   M := (1-x)*N + x*A :

 So my parameter is x, and N, A are numeric (real, symmetric) matricies. I want to plot the eigenvalues as x=0..1, but for a large matrix, say 25x25. Eigenvalues(M) only returns 17 eigenvalues, and more so, it doesnt keep them in the same order when plotting!

My issue is when Maple computes the eigenvalues at x=x0, and at x=x1, it doesnt preserce the order of eigenvalues. i.e. They should vary continuously, but dont. 

This is identical to a problem gdorsch 20 had, and he said

"I want to compute the eigenvalues of this matrix both at a fixed point x0 and at some other arbitrary point x'. The problem is that I need to make sure the ordering of the Eigenvalues remains the same at these two points, so that if I'd go continuously from x0 to x' the eigenvalues would go continuously from Eigenvalues(M(x0)) to Eigenvalues(M(x')), without any flip in the order of the entries."

Any help would be appreciated,

Thanks!