wget http://www-math.mit.edu/~jyu/TrIm/TrIm.zip
unzip TrIm.zip
cd TrIm
You're now ready to use TrIm. Try:
./TrCI.prl example.TrCI.input
./TrIm.prl example.TrIm.input
/project.prl example.project.input
First ssh to calclab1.math.tamu.edu.
In your home directory,
mv .bashrc .bashrc-
cp .bashrc- .bashrc
emacs .bashrc
In emacs, write the following line in the file .bashrc:
export PATH=.:$PATH:/usr/local/sage-2.4-i686-Linux/local/bin
save and exit emacs.
source .bashrc
You're now ready to use Gfan. Save the following in a file named "foo", for
example.
{e+a+b+c+d, a*b*c*d+e*b*c*d+e*a*c*d+e*a*b*d+e*a*b*c}
Then execute:
gfan_tropicalstartingcone < foo > foo.start
gfan_tropicaltraverse < foo.start > foo.fan
The tropical variety is now in foo.fan.
From polynomials to point configurations and polytopes
Here are perl scripts for converting a polynomial into its Newton polytope in
polymake format
or the point configuration of exponents in 4ti2 format.
Download the files polynom.polymake.prl and polynom.4ti2.prl .
chmod 500 polynom.*.prl
Open emacs and write the following example:
[a,b,c]
[2*a^3+3*b^5+5*c^7+a*b*c]
Save as foo and exit emacs.
./polynom.polymake.prl < foo > foo.poly
polymake foo.poly VOLUME
Also look in the file foo.poly.
./polynom.4ti2.prl < foo > foo.mat
The file foo.mat is in the 4ti2 input format. The columns of the
matrix are the exponents of the polynomial.
Caveat: The perl scripts assume that no variable name is a prefix of
another and that each variable appears at most once in each summand (i.e.
don't write x*x).
The symbol * may be omitted but ^ may not be.