Solving 3rd order equation by solve (more on...)

Hi!
 Another case where some way for "chopping" of virtually zero imaginary parts would be of great help.
This comes form a practical case where a 3x3 symmetric matrix diagonalization ( integer matrix elements) was required

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L1: [2,-1,1]$ L2: [-1,2,0]$ L3: [1,0,3]$
HV: matrix(L1,L2,L3)$

load(eigen)$

eivects(HV)$
rectform(%), numer;

 One gets: 
(%o9)
[[[2.445,5.551*10^-17*%i+0.753,3.802-5.551*10^-17*%i],[1,1,1]],[[[1,5.551*10^-16*%i-2.247,-1.802]],[[1,5.551*
10^-17*%i+.8019,-3.384*10^-16*%i-0.445]],[[1,-4.163*10^-16*%i-0.555,2.538*10^-16*%i+1.247]]]]

All eigenvalues and eigenvectors real as expected, but a lot of xxx*10^-16 * %i  stuff .....

 ******************Incidentally

*******************Two procedures that fail in getting the answer:

1) by using

                   rectform(eivects(HV)), numer;

 I get: 

"algsys failure: the eigenvector(s) for the"1"th eigenvalue will be missing."
"algsys failure: the eigenvector(s) for the"2"th eigenvalue will be missing."
"algsys failure: the eigenvector(s) for the"3"th eigenvalue will be missing."
(%o13) [[[2.445,5.551*10^-17*%i+0.753,3.802-5.551*10^-17*%i],[1,1,1]],[[],[],[]]]


2) Trying to get the normalizad vectors: by using 

ueivects(HV);

 I get:   

 << Expression too long to display! >>

Best
________________________________________________________________
Jose Sanchez-Marin.
 Universitat de Valencia.
 Institut de Ciencia Molecular (ICMol).
 Cat.  Jose Beltran Martinez, 2				Phone: +34 96 354 4444
E-46980 Paterna							FAX:   +34 96 354 3576	            
 Spain 				   					e-mail: Jose.Sanchez at uv.es	   
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