Table 1 General double description method for EM computation.

A _q ← q independent rows of A

R ← A _q ^-1

for each unprocessed row A_i•of A do

  J⁺ ← {j ∈ J : A_i•r^j> 0}

  J⁰ ← {j ∈ J : A_i•r^j= 0}

 J^- ← {j ∈ J : A_i•r^j< 0}

R' ← {r^j: j ∈ J⁰ ∪ J⁺}

For (j⁺, j^-) ∈ J⁺ × J^- do

   If and adjacent in R then

end if

end for

R ← R'

End for

R ← R \ { futile two-cycles }

R ← back-configuration of R