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Reed-Solomon: inverting a matrix of GF elements

Started by lindasel November 8, 2008
How does one invert a matrix of GF elements? 
  
Specifically, I would like to see the case of a 3x3 matrix.
Thank you for any information.


On Nov 8, 7:58&#2013266080;pm, "lindasel" <lselt...@alumni.caltech.edu> wrote:
> How does one invert a matrix of GF elements? > > Specifically, I would like to see the case of a 3x3 matrix. > Thank you for any information.
Pretty much the same way as with any other matrix. You just need to do the intermediate arithmetic in GF(p^n) instead of in R or C. - Kenn
More specifically, one step in inverting a conventional matrix is to find
the cofactors from the transpose.  In a 3x3 matrix, for example, there is a
sign change for the cofactors of the second row.  Is there any operation
that has to be done for the second row of the cofactors matrix when a GF
matrix is inverted, or is everything computed with XORs with nothing
different in the second row?

I got the inverse to work.  It wasn't necessary to change anything in the
second row.